Attenuation Relationship Based on Turkish Strong Motion Data

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An attenuation relationship based on Turkish strong motion data

and iso-acceleration map of Turkey

Resat Ulusay*, Ergun Tuncay, Harun Sonmez, Candan Gokceoglu

Hacettepe University, Department of Geological Engineering, 06532 Beytepe, Ankara, Turkey

Received 27 May 2003; accepted 13 April 2004

Available online 9 June 2004

Abstract

This paper presents an attenuation relationship of peak ground acceleration (PGA) derived from Turkish strong motion data

for rock, soil and soft soil sites and an iso-acceleration map of Turkey based on this relationship. For the purpose, among all the

three-component accessible records, 221 records from 122 earthquakes that occurred in Turkey between 1976 and November

2003 were selected. The database was compiled for earthquakes with moment magnitudes (Mw) and PGA values ranging

between 4.1 and 7.5, and 20 and 806 gal, and distances to epicenter considered in the database were between 5 and 100 km.

From the regression analysis of the data, an attenuation equation of PGA considering rock, soil and soft soil conditions was

developed. The PGA values predicted from the equation suggested in this study and those both from a few domestic equations

and some imported equations were compared. In addition, an iso-acceleration map of Turkey was constructed using thesuggested attenuation equation and considering both known active faults and epicenter locations of the earthquakes that have

occurred in Turkey.

D 2004 Elsevier B.V. All rights reserved.

Keywords: Attenuation relationship; Iso-acceleration map; Peak ground acceleration; Strong motion database; Turkey

1. Introduction

In seismic hazard analyses the quantitative descrip-

tion of the ground motions are very important. One of

the ground motion parameters commonly used in

geotechnical and structural engineering analyses is

peak ground acceleration (PGA). Therefore, estima-

tion of this parameter in a precise manner has a prime

importance in engineering design. Major initiatives to

instrument seismically active regions around theworld were undertaken in the twentieth century, and

these instruments have provided a large inventory of

recordings. Data from this inventory are used to

develop empirical strong motion attenuation relation-

ships to estimate earthquake ground motions based on

some characteristics of the earthquakes and local

geology. PGA is the simplest strong-motion parameter

and hence more than 120 attenuation equations have

been derived in the past to predict it (Douglas, 2003).

However, these equations were derived for different

0013-7952/$ - see front matterD 2004 Elsevier B.V. All rights reserved.doi:10.1016/j.enggeo.2004.04.002

* Corresponding author. Fax: +90-312-299-2034.

E-mail address: [email protected] (R. Ulusay).

www.elsevier.com/locate/enggeo

Engineering Geology 74 (2004) 265291


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earthquake regions and fault types, and interplate

versus intraplate. In addition, their data selection

criteria are different, and some of them pertain to

only a single ground type such as rock or firm soil. Asa result of their nature, differences among the esti-

mated PGA values from the existing attenuation

relationships from one region or country to another

result in a limitation in their use. Therefore, the use of

attenuation relationships derived from the records of a

region, where the predictive equations are considered,

shows an increasing tendency between the associated

engineering community.

In Turkey, the seismic hazard zonation map was

published by the Ministry of Public Works and

Settlement of Turkey (1996). Based on this map,

Turkey is divided into five subclasses of seismic zone

with PGA values of >0.4g, 0.30.4g, 0.20.3g, 0.1

0.2g and < 0.1g for zones ranging from I to V,

respectively. The current practice in Turkey is to

directly use the PGA values from the seismic codes

published by the Ministry of Public Works and

Settlement of Turkey (1998). According to the codes,

PGA values of 0.4g, 0.3g, 0.2g and 0.1g are assigned

for zones ranging from I to IV, respectively. However,

in seismic hazard modeling studies for Turkey, some

investigators (e.g. Erdik et al., 1985; Gulkan et al.,

1993; Kayabali, 2002) employed the relationshipssuggested for California, specifically by Joyner and

Boore (1981, 1988) due to some similarities between

the San Andreas Fault in USA and the North Anato-

lian Fault Zone in Turkey. The seismic zoning map of

Turkey have the same setbacks and these are outlined

by Kayabali and Akin (2002). In order to minimize

the effects of the setbacks in the present map, new

maps were constructed by Kayabali (2002) and Kaya-

bali and Akin (2002) using the probabilistic and

deterministic approaches, respectively. However,

Kayabali and Akin (2002) also indicated that theprobabilistic-based maps appear to have employed

relatively large seismic zones, and therefore, deter-

ministic-based seismic map seems to be more realis-

tic. In the construction of the deterministic based iso-

acceleration and seismic zoning maps of Turkey,

Kayabali and Akin (2002) considered only active

faults and ignored locations of the epicenters. In

addition, they compared two domestic attenuation

equations of strong ground motion for the earthquakes

of Turkey developed by Inan et al. (1996) and Aydan

et al. (1996), and some imported equations. Based on

their comparisons, they decided to use the equation

developed by Sadigh et al. (1997) as the appropriate

prediction equation for the construction of their map.However, the equation by Sadigh et al. (1997) does

not account for normal faulting, and it was a non-

sense comparison through the use of the distance to

epicenter instead of hypocentral distance when they

considered the equation, which was developed by

Aydan et al. (1996) modified by Aydan (2001) for

Turkey. The PGA values picked up from this iso-

acceleration map are for bedrock and it is necessary to

carry out site response analyses for the computation of

maximum PGA for soil sites.

Three domestic attenuation relationships of PGA

for the earthquakes of Turkey were suggested by Inan

et al. (1996), Aydan (2001), and Gulkan and Kalkan

(2002). The PGA equation developed by Inan et al.

(1996) is as follows:

log PGA 0:65M 0:9 log R 0:44 1

where M is the earthquake magnitude and R is the

distance to epicenter in kilometers. No distinction is

considered between the records obtained from the

stations founded on rock and soil sites in this atten-

uation relationship. It is also noted that type of the

magnitude employed in the equation and data selec-

tion criteria have not been mentioned in the related

literature. On the other hand, this relationship yields

unusually high values of PGA particularly in near

source areas.

The second attenuation relationship based on a

large database system, which is called TURDIVAZ

and involved recordings at stations on soil and rocky

grounds operated by ERD, KOERI and ITU for the

characteristics of acceleration waves of Turkish earth-

quakes, was developed by Aydan and published in a

report (Aydan, 1997) and in an article (Aydan et al.,1996), respectively. This attenuation relationship is

given in the following form:

amax 2:8e0:9Ms e0:025R 1 2

where amax is the maximum ground acceleration, and

Ms and R are the surface magnitude and the hypocen-

tral distance of a given earthquake, respectively. At the

beginning the number of data employed for the above

equation was 60. This function consists of two expo-

R. Ulusay et al. / Engineering Geology 74 (2004) 265291266


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nential functions, which fundamentally govern the

overall form of attenuation. Two criteria were selected

by its originator in developing this equation: (i) when

the magnitude is zero, there should not be any groundmotion, and (ii) it should also be capable of estimating

strong ground motions of large earthquakes of Turkey

with known accelerations. However, Aydan recog-

nized a small problem with Eq. (2), that is, the ground

acceleration will have a negative value when R goes to

infinity although it will almost no effect on the

estimated maximum ground acceleration. Therefore,

form of the equation was slightly modified in order to

satisfy the condition, that is, the maximum ground

acceleration should be nil when R goes to infinity, and

re-written in the following form (Aydan, 2001).

amax 2:8e0:9Ms 1e0:025R 3

The coefficient 2.8 appearing in Eq. (3) is considered

for soils and reduced to 0.56 for firm soils and rocky

grounds as the site condition coefficient. This attenu-

ation relationship generally simulated the records of

big earthquakes of Turkey.

The most recent attenuation relationship for Turkey

was developed by Gulkan and Kalkan (2002) by using

the same general form of the equation proposed for

shallow earthquakes in Western North America by

Boore et al. (1997). The ground motion parameter

estimation is as follows:

ln Y b1 b2M 6 b3M 62 b5ln r

bv lnVs=VA; 4

r R2cl h20:5; 5

where Yis the ground motion parameter (PGA or PSAin g), M is (moment) magnitude; Rcl is the closest

horizontal distance between the recording station and

a point on the horizontal projection of the rupture

zone on the earths surface in km; Vs is the shear wave

velocity for the station in m/s; b1, b2, b3, b5, h, bv and

VA are the parameters to be determined. Here h is a

fictitious depth and VA is a fictitious shear-wave

velocity that is determined by regression. Gulkan

and Kalkan (2002) utilized 47 horizontal components

of only main shocks of 19 earthquakes with magni-

tudes Mwz 5 occurred in Turkey between 1976 and

1999, and omitted the PGA values less than 40 gal.

Half of the data they employed was from the devas-

tating Kocaeli and Duzce earthquakes of 1999. Basedon the Kocaeli and Duzce events, Gulkan and Kalkan

(2002) compared their equations to some imported

attenuation relationships not specifically from record-

ings in Turkey, and concluded that the imported

relationships overestimate the peak and spectral ac-

celeration values for up to about 1520 km, for larger

distances the reverse holds. These investigators also

recommended that as additional strong motion

records, shear-wave velocity profiles for recording

sites and better determined distance data become

available for Turkey, their attenuation relationship

can be progressively modified and improved, and its

uncertainties reduced.

On the basis of the abovementioned information

and brief evaluation, the authors of the present paper

believe that the attenuation relationships derived in

other countries and for different tectonic regimes

should be carefully utilized for seismic assessments

in Turkey. Therefore, the authors considered that

derivation of an attenuation equation for PGA based

on a larger database as a contributory study to those

carried out to develop domestic equations for Turk-

ish earthquakes, and its use in practice may becomeuseful. In this study, an attempt was made to derive

an attenuation equation of PGA for rock, soil and

soft soil sites in Turkey. The database, employed in

this study included the records from the earthquakes

of Mwz 4 between 1976 and November 2003.

Among all the three-component records, 221 records

of 122 earthquakes were selected for regression

analysis, and effects of the site conditions were also

considered. From the regression analysis of data, the

equation to predict PGA for the sites underlain by

rock, soil and soft soil were established. The PGAvalues estimated from the equation developed in this

study and those from some previous domestic atten-

uation equations and some imported models based

on worldwide data were compared. In addition,

using the proposed attenuation equation and consid-

ering the epicenters of the earthquakes and the

known active faults of Turkey, PGA values were

calculated. Then the calculated PGA values were

contoured to obtain an iso-acceleration map of

Turkey. The PGA value picked up from the map

R. Ulusay et al. / Engineering Geology 74 (2004) 265291 267


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for any site is for bedrock, and when it is multiplied

by the coefficients, the PGA of soil and soft soils

can be found.

2. Data selection criteria and database

Installation of the acceleration recorders was initi-

ated in Turkey in 1973 in relation with the project of

Strong Ground Motion Network of Turkey, under the

responsibility of the Earthquake Research Department

(ERD) of the General Directorate of Disaster Affairs

(GDDA). Since that date, the strong motion network

has grown considerably, and the first strong motion

recording of an earthquake was obtained in Denizli on

19 August 1976, western Turkey. While the total

number of instruments was 120 up to 2001, at the

end of 2002 the total number of the instruments

reached to 163 (ERD, 2003). Ninety-six of these

accelerometers are digital, while 67 instruments are

analog. The accelerometric sites in Turkey are gener-

ally located along the North Anatolian and East

Anatolian Fault Zones and as well as in the southwest-

ern Anatolia. In addition to these instruments forming

the network, a limited number of temporary stations

installed by the Kandilli Observatory and Earthquake

Research Institute of Bogazic i University (KOERI),Ystanbul Technical University (ITU), USGS, Lomont-

Doberty Earth Observatory (LDEO, USA) and Uni-

versite Joseph Fourier after the devastating 1999

Kocaeli Earthquake are also present. The records of

these stations were downloaded from the web sites ofthe Consortium of Organizations for Strong Motion

Observation Systems (COSMOS, 2003) and USGS.

Some of the accelerometric data, available on the

Internet, do not include corresponding earthquake

characteristics (location and magnitude), and there

are some contradictions between different databases.

In order to decrease the number of unknowns and

uncertainties, and consequently improve the reliability

of the derived attenuation equation, additional data

associated with the earthquakes occurred in Turkey

were also found from the Internet sites of ETHZ

(2003), ISESD (2003), USGS-NEIC (2003), ISC

(2003) and HARVARD (2003). Among all-the three-

component accessible records between 1976 and No-

vember 2003, 221 records from 122 earthquakes of

Turkey were selected based on the criteria outlined in

the following paragraphs. Locations of the accelero-

metric sites in Turkey corresponding to the data

selected in this study are shown in Fig. 1.

Exclusion of records based on minimum PGA has

been proposed as selection criteria and they are

reviewed by Douglas (2003). In this study, the acce-

leograms with a PGAz 20 gal were selected consid-ering the criterion by Campbell (1981) to avoid bias in

Fig. 1. The locations of the strong ground motion stations of Turkey employed in this study.



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trigger threshold. The PGA data used in the analysis

were mostly from the stations founded in small

buildings, and the larger horizontal component of

each record was selected.The best scale for scientific and engineering pur-

poses is the moment magnitude (Mw) scale since it is

related to the rupture parameters. Therefore, in this

study earthquake size was characterized by Mw. Be-

cause smaller earthquakes are generally not of engi-

neering significance, the earthquakes with Mwz 4

were considered. However, the magnitudes of the

earthquakes occurred in Turkey are reported by dif-

ferent institutions in various scales. Based on the

database for a total of 170 events in Turkey occurred

between 1976 and November 2003, the numbers of

the magnitudes given by different institutions in Mw,Ms, Mb, Md and ML scales are 96, 95, 150, 75 and 69,

respectively. In other words, Mw values are not

available for all events. Therefore, it was decided to

derive moment magnitude for all records, to provide a

uniform and reliable scale for the attenuation relation-

ship, which was developed in this study. For the

purpose, values of Mw (from ETHZ and Harvard)

were correlated to Ms (from ETHZ, ISC, USGS,

Fig. 2. Correlations between the reported Mw, and the reported Ms, Mb, Md and ML values for Turkish earthquakes (r: correlation coefficient;

S.D.: standard deviation).



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Harvard and ISESD), Mb (from ETHZ, ISC, USGS

and Harvard), Md and ML (from ERD) values. Using

data sets of 54, 92, 28 and 27 between MsMw, Mb

Mw, MdMw and MLMw, respectively, the relation-ship and conversion equations derived between Mwand other magnitude scales are given in Fig. 2. These

relationships yielded considerably high correlation

coefficients greater than 0.9. Of the 122 earthquakes

considered in this study based on the selection criteria,

magnitudes of 49 earthquakes have been directly

presented in Mw scale. Therefore, magnitudes in Mwscale for the rest (73 earthquakes) were derived from

the equations given in Fig. 2 (39, 18, 10 and 6 Mwvalues from Ms, Mb, Md and ML, respectively).

The distance to epicenter is the easiest measure to

use because the epicenter is the location information

given for all earthquakes. For small earthquakes, the

use of distance to epicenter in hazard analysis is

reasonably straightforward because easily available

catalogues of previous epicenters can be used as the

future sources or if line or surface source zones are

used then epicenters can be distributed on these

source zones (Douglas, 2003). For large-magnitude

earthquakes, the closest distance measures are gen-

erally preferred over the point source distances, such

as distance to the surface projection of the rupture

(e.g. Joyner and Boore, 1981) or rupture distance

(Campbell, 1981), at least for records from earth-quakes with Mw>6.5. However, for most of the

events, particularly for small events that have oc-

curred in Turkey, rupture surfaces have not been

defined clearly, and these distances are more difficult

to estimate. One of the other distance measures that

is available for most earthquakes is hypocentral

distance (Rh). However, accurate measures of focal

depth are often difficult, and therefore, estimation of

hypocentral distance is affected from this limitation.

Most damaging earthquakes occur within a shallow

region of the crust (about the top 30 km) and hence

Rh and distance to epicenter (Rc) become equal at

intermediate and large distances (Douglas, 2003). It

is also noted that the values of focal depth reported

by various institutions can be different as shown in

Fig. 3 for some earthquakes with Mw>5.5 from

Turkey. In this study, due to the abovementioned

reasons, distance to epicenter, Re, is preferred to be

used as site source distance in PGA estimation

relation. Minimum and maximum distance criteria

Fig. 3. Comparison of the depth values of some selected earthquakes of Turkey (Mw>5.5) reported by various institutions (earthquake numbers

refer to the earthquakes given in Table 1).



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are sometimes applied. A minimum distance criterion

of 2 km was applied by Wang et al. (1999) because

2 km is the minimum error in epicentral locations

and hence including records from smaller distancesmay give errors in the results. As mentioned by

Douglas (2003), only records associated with reliable

measures were used by some investigators (Camp-

bell, 1981; Sabetta and Pugliese, 1987) by including

only earthquakes with locations (epicenters or rup-

ture distance) known to within 5 km or less. On the

other hand, in the majority of the strong ground

motion relations suggested for tectonically active

regions (e.g. Boore et al., 1997; Campbell, 1997;

Sadigh et al., 1997) the upper bound for sitesource

distance is taken 100 km, which is the range where

ground motions have engineering significance.

Therefore, 5 and 100 km were taken as the lower

and upper bounds of the distance to epicenter,

respectively, and the records, for which the distance

to epicenter does not fall into this range were

omitted.

One of the extremely difficult items in determining

the site condition coefficient of the attenuation relation-

ships is the ground conditions. Local site conditions at

an acceleograph station can affect the strong motion

recorded. Therefore, attempts have been made in most

ground estimation relations to model the effect of near-surface ground conditions or strong motion. Data

selection criteria, which seek to limit the acceleograms

used to those recorded at stations with similar local site

conditions, are the simplest techniques. While the

widely accepted method quantitatively define the

near-surface material based on shear-wave velocity,

Vs, beneath the station. However, without consistent

site classifications for the attenuation relations, it is

often difficult to know how to apply the relations to a

specific site. But information on Vs is currently lacking

for the stations in Turkey. Based on their experiencewith the Iranian data, Zare and Bard (2002) classified

the records from Turkey for site conditions according

to the frequency band of the fundamental frequency

based on their H/V ratio. This ratio was chosen based

on the location of the broadened H/V spectral ratios

and the value of its amplitude. These investigators

suggest that this is the only method that may reveal

the site response, in the absence of any reliable geo-

logical and geotechnical data, such as Vs values. In

brief, Zare and Bard (2002) divided soil groups for

Turkey in ascending order for Vs and fundamental

frequency (fo) site category: 1rock and hard alluvial

soil corresponds to Vs>800 m/s, fo>15 Hz, site category

2alluvial sites (500 < Vs


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Table 1

Strong ground motion records used in the development of the attenuation relationship for peak ground acceleration (PGA) for Turkey

No. Station Code Station

coordinates

Earthquake

(date)

Epicenter

coordinates

Re(km)

PGA (gal) Site

C.

Mw

Lat. Lon. Lat. Lon. N S E W U D

1 Denizli Meteoroloji Mud. DNZ 37.814 29.112 19.08.1976 37.71 29 15.2 348.53 290.36 173.29 2 5.5a

2 Cerkes Meteoroloji Mud. CER 40.88 32.91 05.10.1977 41.01 33.57 57.2 36.03 38.94 16.18 3 5.8

3 Izmir Meteoroloji Mud. IZM 38.4 27.19 09.12.1977 38.35 27.23 6.6 158.91 272.97 87.25 2 5.2a

4 Malatya Meteoroloji Mud. MLT 38.35 38.34 21.09.1978 37.97 38.59 47.5 14.08 35.79 21.12 1 5.0a

5 Muradiye Meteoroloji Mud. M UR 39.03 43.7 11.04.1979 39.12 43.91 20.7 46.04 45.22 24.67 1 5.0a

6 Dursunbey Kandilli

Gozlem Ist.

DUR 39.67 28.53 18.07.1979 39.66 28.65 10.3 232.29 288.25 199.77 2 5.3

7 Hatay Bayindirlik ve

Iskan Mud.

HTY 36.25 36.11 30.06.1981 36.17 35.89 21.6 154.05 135.6 144.32 2 4.6a

8 Gonen Meteoroloji Mud. GNN 40.08 27.68 05.07.1983 40.33 27.21 48.6 50.11 46.77 37.68 2 6.1

9 Edincik Kandilli Gozlem Ist. EDC 40.36 27.89 05.07.1983 40.33 27.21 57.7 53.44 46.51 31.67 1 6.1

10 Tekirdag Meteoroloji Mud. TKR 40.96 27.53 05.07.1983 40.33 27.21 75.0 29.89 34.91 17.19 1 6.1

11 Edremit Meteoroloji Mud. EDR 39.61 27.03 05.07.1983 40.33 27.21 81.4 25.38 27.78 17.47 2 6.1

12 Balikesir Meteoroloji Mud. BLK 39.66 27.86 05.07.1983 40.33 27.21 92.7 22.55 20.71 24.72 2 6.1

13 Horasan Meteoroloji Mud. HRS 40.04 42.17 30.10.1983 40.35 42.18 34.4 173.3 150.26 87.92 2 6.6

14 Erzurum Meteoroloji Mud. ERZ 39.906 41.256 30.10.1983 40.35 42.18 92.7 35.49 24.99 31.94 1 6.6

15 Foca Gumruk Mud. FOC 38.64 26.77 17.06.1984 38.87 25.68 97.8 24.17 23 23.52 1 5.5b

16 Kigi Meteoroloji Mud. 39.34 40.28 12.08.1985 39.95 39.77 80.6 163.06 89.1 42.63 2 4.9a

17 Koycegiz Meteoroloji Mud. KOY 3 6.97 28.694 06.12.1985 36.97 28.85 13.8 103.24 114.46 68.59 2 5.1a

18 Golbasi Devlet Hastanesi GOL 37.781 37.641 05.05.1986 38.02 37.79 29.6 114.7 76.04 38.96 1 6.0

19 Kusadasi Meteoroloji Mud. KUS 37.861 27.266 01.06.1986 37.96 27.39 15.5 55.52 94.43 54.16 2 4.1c

20 Golbasi Devlet Hastanesi GOL 37.781 37.641 06.06.1986 38.01 37.91 34.7 68.54 34.42 18.01 1 5.8

21 Malatya Meteoroloji Mud. MLT 38.35 38.34 06.06.1986 38.01 37.91 53.2 23.57 24.81 26.04 1 5.8

22 Muradiye Meteoroloji Mud. MUR 39.03 43.7 20.04.1988 39.11 44.12 37.3 49.5 51.18 20.65 1 5.5

23 Foca Gumruk Mud. FOC 38.64 26.77 04.08.1988 38.86 27 31.5 31.61 41.4 28.32 1 4.7c

24 Istanbul Bayindirlik veIsk. Mud.

IST 41.08 29.09 12.02.1991 40.8 29.09 31.1 27.58 18.21 9.68 2 5.3a

25 Amasya Meteoroloji Mud. AMS 40.63 35.87 12.02.1992 40.58 35.8 8.1 37.1 29.03 2 4.94 3 5.1b

26 Erzincan Meteoroloji Mud. ERC 39.752 39.487 13.03.1992 39.72 39.63 12.7 470.92 404.97 238.55 2 6.6

27 Tercan Meteoroloji Mud. TER 39.777 40.391 13.03.1992 39.72 39.63 65.3 39.38 26.97 22.67 2 6.6

28 Refahiye Kaymakamlik

Binasi

REF 39.901 38.769 13.03.1992 39.72 39.63 76.2 67.21 85.93 31.57 2 6.6

29 Erzincan Meteoroloji Mud. ERC 39.752 39.487 15.03.1992 39.53 39.93 45.2 32.45 39.3 18.47 2 5.9

30 Erzincan Eksisu SERE 39.733 39.783 15.03.1992 39.53 39.93 25.8 112.5 40.7 3 5.9

31 Izmir Meteoroloji Mud. IZM 38.4 27.19 06.11.1992 38.16 26.99 31.8 30.49 38.34 21.19 2 6.0

32 Kusadasi Meteoroloji Mud. KUS 37.861 27.266 06.11.1992 38.16 26.99 41.1 83.49 71.8 62.1 2 6.0

33 Ilica Meteoroloji Mud. ILI 38.31 26.31 06.11.1992 38.16 26.99 61.6 16.65 37.81 25.77 2 6.0

34 Cesme Meteorological

Station

CES 38.333 26.317 06.11.1992 38.16 27 62.6 28.3 14.9 2 6.0

35 Islahiye Meteoroloji Mud. ISL 37.05 36.6 03.01.1994 37 35.84 67.6 20.57 19.43 19.14 2 5.3a

36 Foca Gumruk Mud. FOC 38.64 26.77 24.05.1994 38.66 26.54 20.1 36.06 49.8 29.6 1 5.5

37 Foca Gumruk Mud. FOC 38.64 26.77 24.05.1994 38.76 26.6 19.9 57.65 46.84 25.6 1 5.5a

38 Ilica Meteoroloji Mud. ILI 38.31 26.31 24.05.1994 38.76 26.6 56.0 24.91 26.88 14.6 2 5.5a

39 Koycegiz Meteoroloji Mud. KOY 36.97 28.694 13.11.1994 36.97 28.89 17.4 72.79 96.51 57.91 2 5.4a

40 Koycegiz Meteoroloji Mud. KOY 36.97 28.694 13.11.1994 37 28.82 11.7 26.6 20.78 20.63 2 4.7c

41 Koycegiz Meteoroloji Mud. KOY 36.97 28.694 13.11.1994 36.96 28.8 9.5 57.16 39.95 34.25 2 5.4

42 Koycegiz Meteoroloji Mud. KOY 36.97 28.694 13.11.1994 37.17 28.87 27.1 25.54 23.78 20.08 2 4.3d

43 Tercan Meteoroloji Mud. TER 39.777 40.391 29.01.1995 39.98 40.99 55.8 44.98 48.52 24.81 2 5.2

44 Van Bayindirlik ve

Iskan Mud.

VAN 38.504 43.406 26.02.1995 38.6 43.33 12.5 28 15.5 15.5 2 5.2b

45 Tekirdag Meteoroloji Mud. TKR 40.96 27.53 13.04.1995 40.85 27.67 16.9 38 45 11 1 5.0a



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coordinates

Earthquake

(date)

Epicenter

coordinates

Re(km)

PGA (gal) Site

C.

Mw

Lat. Lon. Lat. Lon. N S E W U D46 Tekirdag Meteoroloji Mud. TKR 40.96 27.53 18.04.1995 40.8 27.84 31.5 25.5 34.5 8 1 4.9c

47 Dinar Meteoroloji Mud. DIN 38.06 30.155 26.09.1995 38.04 30.03 11.2 106 182.73 75.56 3 5.0a

48 Dinar Meteoroloji Mud. DIN 38.06 30.155 26.09.1995 38.09 30.01 13.1 54.26 81.02 48.77 3 5.1a


50 Dinar Meteoroloji Mud. DIN 38.06 30.155 28.09.1995 38.56 30.47 61.9 39.62 42.72 12.11 3 4.2c

51 Dinar Meteoroloji Mud. DIN 38.06 30.155 01.10.1995 38.04 30.09 6.1 91.33 171.79 37.66 3 4.3c

52 Dinar Meteoroloji Mud. DIN 38.06 30.155 01.10.1995 38.11 30.05 10.7 281.63 329.72 150.68 3 6.4

53 Cardak Saglik Ocagi CRD 37.825 29.668 01.10.1995 38.11 30.05 46.0 65.07 61.3 98.47 2 6.4

54 Burdur Meteoroloji Mud. BRD 3 7.723 30.294 01.10.1995 38.11 30.05 48.0 41.61 43.92 33.86 2 6.4

55 Denizli Meteoroloji Mud. DNZ 37.814 29.112 01.10.1995 38.11 30.05 88.5 20 10 10 2 6.4


57 Cardak Saglik Ocagi CRD 37.825 29.668 01.10.1995 38.1 30.02 43.4 24.83 20.87 13.18 2 5.4a


a

59 Dinar Meteoroloji Mud. DIN 38.06 30.155 05.10.1995 38.04 30.1 5.3 104.32 128.84 80.48 3 5.2b

60 Dinar Meteoroloji Mud. DIN 38.06 30.155 06.10.1995 38.03 30.09 6.6 98.85 168.08 44.57 3 5.0b

61 Dinar Cezaevi DCE 38.075 30.161 11.10.1995 38.12 30.18 5.3 44.74 41.14 1 5.93 2 4.3a

62 Dinar Jandarma Karakolu DJK 38.069 30.16 11.10.1995 38.12 30.18 5.9 31.31 63.6 13.18 2 4.3a

63 Dinar Devlet Hastanesi DDH 38.067 30.171 11.10.1995 38.12 30.18 5.9 40.53 25.15 13.31 1 4.3a

64 Dinar Koy Hizmetleri DKH 38.053 30.139 11.10.1995 38.12 30.18 8.3 86.24 47.18 14.53 2 4.3a

65 Erzincan Bayindirlik

ve Isk Mud.

ERC 39.743 39.512 05.12.1995 39.3 40.3 83.5 28.27 24.02 23.99 2 5.8


ve Isk Mud.

ERC 39.743 39.512 05.12.1995 39.3 40.1 70.4 27.78 22.85 17.64 2 5.9a


ve Isk Mud.

ERC 39.743 39.512 14.02.1996 39.61 39.23 28.3 47.91 38.47 35.15 2 4.2d

68 Kusadasi Meteoroloji Mud. KUS 37.861 27.266 20.02.1996 38.25 27.13 44.8 15.45 21.35 13.36 2 4.7b

69 Kusadasi Meteoroloji Mud. KUS 37.861 27.266 02.04.1996 37.78 26.64 55.7 21.33 33.44 22.46 2 5.470 Tekirdag Meteoroloji Mud. TKR 40.96 27.53 14.04.1996 40.8 27.45 19.0 10.5 21 7 1 4.1c

71 Osmancik Belediye Binasi OSM 4 0.97 34.83 14.08.1996 40.74 35.29 46.3 15.65 30.88 11.62 2 5.7

72 Amasya Bayindirlik

ve Isk Mud.

AMS 40.63 35.87 14.08.1996 40.74 35.29 50.3 26.5 54 25.5 3 5.7


ve Isk Mud.

AMS 40.63 35.87 14.08.1996 40.79 35.23 56.7 20 33.5 16.5 3 5.6

74 Merzifon Meteoroloji Mud. MRZ 40.88 35.49 14.08.1996 40.79 35.23 24.0 33.38 102.34 28.53 2 5.6

75 Buldan Kaymakamlik Binasi BLD 38.045 28.834 21.01.1997 38.12 28.92 11.2 24.37 38.51 28.02 2 5.2


Iskan Mud.

HTY 36.25 36.11 22.01.1997 36.14 36.12 12.2 134.5 149 89.5 2 5.7


Iskan Mud.

HTY 36.25 36.11 23.01.1997 36.16 36.33 22.1 27.5 19 16 2 4.1c


ve Isk. Mud.

AMS 40.63 35.87 28.02.1997 40.68 35.3 48.3 21 21 14.5 3 5.4a

79 Sakarya Bayindirlik

ve Isk. Mud.

SKR 40.739 30.384 21.10.1997 40.7 30.42 5.3 33.87 71.59 15.14 1 4.3a

80 Gelibolu Karayollari Mud. GLB 40.43 26.67 25.10.1997 40.49 26.43 21.3 42.42 19.43 8.75 2 5.2a

81 Edremit Meteoroloji Mud. EDR 39.583 27.016 05.03.1998 39.68 26.7 29.1 27.11 20.06 14.17 2 5.0a


83 Cardak Saglik Ocagi CRD 37.825 29.668 04.04.1998 38.14 30.04 47.8 24.48 27.88 19.15 2 5.2

84 Horasan Meteoroloji Mud. HRS 40.043 42.173 13.04.1998 39.91 41.61 50.1 38.5 32.5 23.5 2 5.2

85 Elazig Bayindirlik Mud. ELZ 38.672 39.193 09.05.1998 38.38 38.94 39.2 25.5 15 17.5 2 5.1

86 Ceyhan Tarim Ilce Mud. CYH 37.05 35.81 27.06.1998 36.85 35.55 32.0 273.55 223.28 86.47 3 6.3

Table 1 (continued)

(continued on next page)



10/27


coordinates

Earthquake

(date)

Epicenter

coordinates

Re(km)

PGA (gal) Site

C.

Mw

Lat. Lon. Lat. Lon. N S E W U D87 Karatas Meteoroloji Mud. KRT 36.561 35.367 27.06.1998 36.85 35.55 36.0 28.5 33.1 19.74 2 6.3

88 Mersin Meteoroloji Mud. MRS 36.83 34.65 27.06.1998 36.85 35.55 80.0 119.29 132.12 22.05 3 6.3


Iskan Mud.

HTY 36.213 36.16 27.06.1998 36.85 35.55 89.3 27.07 25.79 12.36 2 6.3

90 Islahiye Meteoroloji Mud. ISL 37.05 36.6 27.06.1998 36.85 35.55 95.8 21.35 18.22 14.11 2 6.3

91 Nacarli Koyu NAC 36.87 35.617 04.07.1998 36.84 35.44 16.1 24.1 20 19.6 1 5.4

92 Kilicli Koyu Ilkogretim

Okulu

KIL 37.081 35.455 04.07.1998 36.84 35.44 26.8 122.1 132.9 35.9 3 5.4

93 Baklal Koyu Saglik Ocagi BKL 37.033 35.633 04.07.1998 36.84 35.44 27.4 28.3 20.8 13.8 3 5.4

94 Mersin Meteoroloji Mud. MRS 36.83 34.65 04.07.1998 36.84 35.44 70.2 46.7 60.9 12.1 3 5.4

95 Baklali Koyu Saglik Ocagi BKL 37.033 35.633 04.07.1998 36.88 35.62 17.0 22 23.1 12.6 3 4.6a

96 Kilicli Koyu Ilkogretim

Okulu

KIL 37.081 35.455 04.07.1998 36.88 35.62 26.7 90 90.7 25 3 4.6a

97 Bornava Ziraat Fakultesi BRN 38.455 27.229 09.07.1998 38.08 26.68 63.4 27 12.5 5.6 3 5.0a

98 Horasan Tarim Ilce Mud. HRS 40.043 42.173 19.12.1998 39.82 42.13 25.0 26.5 19.5 14 2 4.9a

99 Elazig Bayindirlik Mud. ELZ 38.672 39.193 13.04.1999 38.53 39.25 16.5 12.5 31 9.5 2 4.5a

100 Tosya Meteoroloji Mud. TOS 41.013 34.037 16.06.1999 40.96 33.87 15.2 34.36 30.49 17.76 2 4.1a

101 Erzurum Bayindirlik

ve Isk. Mud.

ERZ 39.903 41.262 20.07.1999 39.53 41.28 41.4 33.51 29.88 23.5 1 4.8a

102 Yarimca Petkim Tesisleri 40.7639 29.762 17.08.1999 40.76 29.97 17.5 230.22 322.2 3 7.5


ve Isk. Mud.

SKR 40.737 30.384 17.08.1999 40.76 29.97 34.9 407.04 259 1 7.5

104 Iznik Karayollari Sefligi IZN 40.437 29.691 17.08.1999 40.76 29.97 42.9 91.89 123.32 3 7.5

105 Gebze Tubitak Marmara

A. M.

GBZ 4 0.82 29.44 17.08.1999 40.76 29.97 45.1 284.82 141.45 2 7.5

106 Darica Arcelik Arge Binasi 40.8236 29.3607 17.08.1999 40.76 29.97 51.7 2 11.37 133.68 2 7.5

107 Heybeliada Sanatoryum HAS 40.8688 29.087 17.08.1999 40.76 29.97 75.2 56.15 110.23 1 7.5108 Goynuk Devlet Hastanesi GYN 40.385 30.734 17.08.1999 40.76 29.97 76.7 117.9 137.7 129.9 2 7.5

109 Istanbul Bayindirlik

ve Isk. Mud.

IST 41.08 29.09 17.08.1999 40.76 29.97 81.9 60.67 42.66 36.22 2 7.5

110 Levent Yapi Kredi Plaza 41.0811 29.0111 17.08.1999 40.76 29.97 88.0 41.08 35.52 1 7.5

111 Fatih Turbesi FAT 41.0196 28.95 17.08.1999 40.76 29.97 90.4 189.39 161.87 3 7.5

112 Bursa Tofas Fabrikasi 40.2605 29.068 17.08.1999 40.76 29.97 94.2 100.89 100.04 3 7.5

113 Bursa Sivil Savunma Mud. BRS 40.184 29.131 17.08.1999 40.76 29.97 95.5 54.32 45.81 25.73 2 7.5

114 Yesilkoy Havalimani 40.9823 28.8199 17.08.1999 40.76 29.97 99.7 90.21 84.47 2 7.5

115 ITU Istanbul Maslak MSK 41.104 29.019 17.08.1999 40.76 29.97 88.5 47.7 27.1 1 7.5

116 ITU Istanbul Mecidiyekoy MCD 41.065 28.997 17.08.1999 40.76 29.97 88.4 61.8 27.5 2 7.5

117 ITU Istanbul Zeytinburnu ZYT 4 0.986 28.908 17.08.1999 40.76 29.97 92.6 112 46.8 3 7.5

118 ITU Istanbul K.M.Pasa KMP 41.003 28.928 17.08.1999 40.76 29.97 91.6 128.3 84.2 3 7.5

119 ITU Istanbul Atakoy ATK 40.989 28.849 17.08.1999 40.76 29.97 97.5 161.1 61.6 3 7.5

120 Izmit Meteoroloji Istasyonu IZT 40.761 29.907 17.08.1999 40.76 29.97 5.3 219.2 139.2 1 7.5

121 Akyazi Orman Isletme

Mud.

. 40.67 30.622 22.08.1999 40.69 30.7 7.0 33.6 35 19.9 3 5.3a

122 Golyaka Jandarma Kislasi GLY 40.799 31.003 22.08.1999 40.69 30.7 28.3 27.5 21.4 9.9 3 5.3a

123 Yarimca Petkim 40.7639 29.762 31.08.1999 40.75 29.92 13.4 20.8 14 10.1 3 5.1


ve Isk. Mud.

SKR 40.737 30.384 31.08.1999 40.75 29.92 39.1 24.41 17.06 8.42 1 5.1

125 Sapanca Saglik Ocagi SPN 40.688 30.257 31.08.1999 40.75 29.92 29.3 30.5 31.7 24.4 3 5.1

126 USGS Golden Station tyw 40.7 30.38 31.08.1999 40.75 29.92 39.5 23.50 24.69 14.66 3 5.1

127 USGS Golden Station KOR 40.76519 29.79347 31.08.1999 40.75 29.92 10.9 36.34 32.08 14.39 1 5.1

128 USGS Golden Station TUN 40.75704 29.78836 31.08.1999 40.75 29.92 11.2 46.34 56.97 24.18 2 5.1

129 USGS Golden Station TUS 40.75455 29.78965 31.08.1999 40.75 29.92 11.1 33.76 60.33 22.89 2 5.1

Table 1 (continued)



11/27


coordinates

Earthquake

(date)

Epicenter

coordinates

Re(km)

PGA (gal) Site

C.

Mw

Lat. Lon. Lat. Lon. N S E W U D130 USGS Golden Station TUW 40.75646 29.78672 31.08.1999 40.75 29.92 11.4 46.64 36.89 26.47 2 5.1

131 USGS Golden Station TYN 40.71192 30.39047 31.08.1999 40.75 29.92 40.3 17.71 19.89 9.40 3 5.1

132 USGS Golden Station TUN 40.75704 29.78836 31.08.1999 40.73 29.95 14.1 23.46 32.44 14.71 2 4.7a

133 USGS Golden Station TUS 40.75455 29.78965 31.08.1999 40.73 29.95 13.9 34.40 56.47 15.66 2 4.7a

134 USGS Golden Station TUW 40.75646 29.78671 31.08.1999 40.73 29.95 14.2 24.31 30.20 19.14 2 4.7a

135 USGS Golden Station KOR 40.76517 29.79343 06.09.1999 40.77 29.73 5.4 57.18 24.62 22.71 1 4.1c

136 USGS Golden Station TUW 40.75644 29.78671 06.09.1999 40.77 29.73 5.1 46.16 44.37 38.72 2 4.1c


ve Isk. Mud.

40.737 30.384 13.09.1999 40.77 30.1 24.2 42.21 50.6 23.35 1 5.8

138 Yarimca Petkim . 40.7639 29.762 13.09.1999 40.77 30.1 28.5 86 89.9 50 3 5.8

139 Heybeliada Senatoryum . 40.8688 29.087 13.09.1999 40.77 30.1 85.9 19.2 35.4 31.6 1 5.8

140 Tepetarla Koyu Muhtar Evi . 40.72 30.079 13.09.1999 40.77 30.1 5.9 595.8 332.9 186.8 3 5.8

141 Bahcecik Seymen Kislasi . 40.71 29.907 13.09.1999 40.77 30.1 17.6 300.4 379.4 70.7 2 5.8142 USGS Golden Station KOR . 40.76505 29.79332 13.09.1999 40.77 30.1 26.1 91.10 108.40 58.30 1 5.8

143 USGS Golden Station SUB . 40.6869 29.49396 13.09.1999 40.77 30.1 52.5 29.40 42.00 18.60 1 5.8

144 USGS Golden Station DOR 40.77736 29.51404 13.09.1999 40.77 30.1 49.9 20.61 23.29 25.47 1 5.8

145 USGS Golden Station OIL 40.75551 29.78091 13.09.1999 40.77 30.1 27.2 151.51 164.09 54.42 2 5.8

146 USGS Golden Station TUW 40.75644 29.78668 13.09.1999 40.77 30.1 26.7 107.24 110.07 55.71 2 5.8

147 USGS Golden Station TYN 40.71190 30.39040 13.09.1999 40.77 30.1 25.6 56.24 52.41 21.63 3 5.8

148 USGS Golden Station TYR 40.73701 30.38008 13.09.1999 40.77 30.1 24.2 47.29 50.98 29.32 1 5.8

149 USGS Golden Station TYW 40.70923 30.39163 13.09.1999 40.77 30.1 25.8 46.41 47.20 24.86 3 5.8

150 USGS Golden Station TYR 40.73702 30.38009 17.09.1999 40.77 30.13 21.6 46.97 70.51 19.76 1 4.2a


ve Isk. Mud.

SKR 40.737 30.384 19.09.1999 40.64 30.52 15.7 18.68 32.53 11.41 1 4.3a

152 USGS Golden Station TYR 40.73705 30.38010 24.09.1999 40.77 30.23 13.3 15.46 26.03 15.96 1 4.3d

153 Bahcecik S eymen Kislasi BHC 40.71 29.907 29.09.1999 40.74 29.33 49.0 74.2 91.5 21.6 2 5.2a

154 Sapanca Saglik Ocagi . 40.688 30.257 29.09.1999 40.74 29.33 78.8 21.2 17.6 10.2 3 5.2a

155 USGS Golden Station DOR 40.77736 29.51404 29.09.1999 40.74 29.33 16.3 200.24 182.35 70.88 1 5.2a

156 USGS Golden Station KOR 40.76512 29.79343 29.09.1999 40.74 29.33 39.6 58.59 109.65 21.08 1 5.2a

157 USGS Golden Station OIL 40.75549 29.78091 29.09.1999 40.74 29.33 38.5 219.49 208.36 28.68 2 5.2a

158 USGS Golden Station TUW 40.75644 29.78673 29.09.1999 40.74 29.33 39.0 92.98 125.71 26.67 2 5.2a

159 USGS Golden Station TYW 40.70924 30.39165 29.09.1999 40.74 29.33 90.7 18.17 26.65 8.77 3 5.2a

160 USGS Golden Station SUB . 40.6869 29.49396 29.09.1999 40.74 29.33 15.2 109.70 96.40 76.30 1 5.2a

161 USGS Golden Station YAR 40.64472 29.27490 20.10.1999 40.83 29.03 29.6 23.49 30.94 12.06 1 5.2a

162 LDEO Station No.

C0362 CH

. 40.67 30.666 07.11.1999 40.7 30.72 5.7 51.9 48 63.1 2 5.0a


C1061

. 40.72 30.792 07.11.1999 40.7 30.72 6.5 62.7 138.5 64.3 2 5.0a


C1060 BU

. 40.777 30.613 07.11.1999 40.7 30.72 12.5 35.3 25.2 24.4 1 5.0a


ve Isk. Mud.

SKR 40.737 30.384 11.11.1999 40.81 30.2 17.5 206.54 345.28 133.33 1 5.6

166 Yarimca Petkim . 40.7639 29.762 11.11.1999 40.81 30.2 37.2 17.1 23.9 19.5 3 5.6


C1060 BU

. 40.777 30.613 11.11.1999 40.81 30.2 35.2 31.4 41.6 44.4 1 5.6


C1061

. 40.72 30.792 11.11.1999 40.81 30.2 51.2 44.4 50.8 20.1 2 5.6


ve Isk. Mud.

SKR 40.737 30.384 11.11.1999 40.88 30.3 17.4 39.795 78.49 20.08 1 4.1c

170 Duzce Meteoroloji Mud. DZC 40.85 31.17 12.11.1999 40.74 31.21 12.7 407.69 513.78 339.64 3 7.2

Table 1 (continued)

(continued on next page)



12/27


coordinates

Earthquake

(date)

Epicenter

coordinates

Re(km)

PGA (gal) Site

C.

Mw

Lat. Lon. Lat. Lon. N S E W U D171 Mudurnu Kaymakamlik

Binasi

40.463 31.182 12.11.1999 40.74 31.21 30.8 120.99 58.34 1 7.2

172 Bolu Bayindirlik

ve Iskan Mud.

BOL 40.747 31.61 12.11.1999 40.74 31.21 33.7 739.51 805.88 200.13 3 7.2


ve Isk. Mud.

SKR 40.737 30.384 12.11.1999 40.74 31.21 69.5 17.33 24.72 11.54 1 7.2


C1058 BV

. 40.743 30.876 12.11.1999 40.74 31.21 28.3 109.1 71.4 71.5 2 7.2


C1061

. 40.72 30.792 12.11.1999 40.74 31.21 35.5 124 100.7 48.6 2 7.2


C0362 CH

. 40.67 30.666 12.11.1999 40.74 31.21 46.9 28 40.3 20 2 7.2

177 LDEO Station No.C1060 BU . 40.777 30.613 12.11.1999 40.74 31.21 50.8 51.5 29.8 20.2 1 7.2


ve Iskan Mud.

BOL 40.747 31.61 12.11.1999 40.75 31.1 42.9 21.13 18.07 7.79 3 5.6c


ve Iskan Mud.

BOL 40.747 31.61 12.11.1999 40.75 31.45 13.5 175.95 130.34 57.03 3 5.3c


ve Iskan Mud.

BOL 40.747 31.61 12.11.1999 40.75 31.4 17.7 59.11 60.32 18.7 3 5.4d


ve Iskan Mud.

BOL 40.747 31.61 12.11.1999 40.74 31.4 17.7 27.99 17.15 12.33 3 4.2c


ve Iskan Mud.

BOL 40.747 31.61 12.11.1999 40.75 31.36 21.0 26.23 25.26 21.25 3 4.8c


ve Iskan Mud.

BOL 40.747 31.61 12.11.1999 40.74 31.05 47.1 57.06 48.24 12.99 3 5.6d

184 Sakarya Bayindirlikve Isk. Mud.

SKR 40.737 30.384 13.11.1999 40.78 30.3 8.5 27.99 22.22 10.68 1 5.1a


C1058 BV

. 40.755 31.015 13.11.1999 40.78 30.3 60.7 44.8 57.5 23 2 5.1a


ve Iskan Mud.

BOL 40.747 31.61 13.11.1999 40.75 31.4 17.7 46.75 34.66 14.2 3 4.0a


C1058 BV

. 40.755 31.015 13.11.1999 40.83 31.02 8.4 23.1 22.3 16.3 2 5.0a


C1061

. 40.72 30.792 13.11.1999 40.83 31.02 22.9 65.1 50.5 24 2 5.0a


ve Isk. Mud.

SKR 40.737 30.384 15.11.1999 40.91 30.33 19.7 23.59 20.17 7.97 1 4.5a

190 Duzce Meteoroloji Mud. DZC 40.844 31.149 20.12.1999 40.87 31.01 12.0 20.45 18.75 19.01 3 4.1a


ve Iskan Mud.

BOL 4 0.747 31.61 05.01.2000 40.84 31.3 28.0 24.73 18 10.67 3 4.2c

192 Duzce Meteoroloji Mud. DZC 40.844 31.149 20.01.2000 40.76 31.33 17.8 35.44 55.18 17.26 3 4.8c

193 Duzce Meteoroloji Mud. DZC 4 0.844 31.149 14.02.2000 40.9 31.75 50.9 37.56 29.56 9.15 3 5.2d


ve Isk. Mud.

SKR 40.737 30.384 02.04.2000 40.79 30.23 14.2 59.27 103.82 30.3 1 4.5

195 Denizli Meteoroloji Mud. DNZ 37.812 29.114 21.04.2000 37.85 29.27 14.3 27.56 17 18.13 2 5.4

196 Cerkes Meteoroloji Mud. CER 40.814 32.833 06.06.2000 40.72 32.87 10.9 62.46 63.16 40.25 3 6.1

197 Akyazi Orman Isletme

Mud.

40.67 30.622 23.08.2000 40.68 30.71 7.5 79.01 96.69 30.42 3 5.5


ve Isk. Mud.

SKR 40.737 30.384 23.08.2000 40.68 30.71 28.2 20.84 27.47 15.63 1 5.5

199 Duzce Meteoroloji Mud. DZC 40.844 31.149 23.08.2000 40.68 30.71 41.2 23.29 17.55 9.25 3 5.5

Table 1 (continued)



13/27

the purpose, the site conditions reported in the data-

bases of several institutions and the literature men-

tioned above are carefully compared, and the site

conditions, which were same in more than one data-

base reported by the institutions, were selected. For

the rest of the stations, for which different site con-

ditions are defined by various institutions, the infor-

mation from ERD (2003), Gulkan and Kalkan (2002),

Zare and Bard (2002), Durukal et al. (1998) and

ISESD (2003) were chosen. In addition, site condition

Table 1 (continued)


coordinates

Earthquake

(date)

Epicenter

coordinates

Re(km)

PGA (gal) Site

C.

Mw

Lat. Lon. Lat. Lon. N S E W U D200 Iznik Karayollari Sefligi IZN 40.44 29.75 23.08.2000 40.68 30.71 85.3 21.69 16.21 8.25 3 5.5

201 Denizli Bayindirlik

ve Iskan Mud.

DNZ 37.813 29.114 04.10.2000 37.91 29.04 12.7 49.13 66.38 49.32 2 5.0

202 Burdur Bayindirlik

ve Iskan Mud.

BRD 37.704 30.221 02.02.2001 37.64 30.19 7.6 21.15 30.12 24.02 2 4.6c


ve Isk. Mud.

ERZ 39.903 41.262 29.05.2001 39.85 41.55 25.2 21.88 17.21 15.14 1 4.9


ve Isk. Mud.

ERZ 39.903 41.262 10.07.2001 39.8273 41.62 31.7 19.53 21.94 26.703 1 5.2


ve Iskan Mud.

BOL 40.747 31.61 26.08.2001 40.9455 31.5728 22.3 189.07 131.64 44.06 3 5.2

206 Van Bayindirlik

ve Iskan Mud.

VAN 38.504 43.406 02.12.2001 38.617 43.294 15.9 29.85 24.81 33.78 2 4.8

207 Afyon Bayindirlik

ve Iskan Mud.

AFY 38.792 30.561 03.02.2002 38.581 31.248 64.0 113.5 94 35.5 3 6.6

208 Afyon Bayindirlik

ve Iskan Mud.

AFY 38.792 30.561 03.02.2002 38.685 30.835 26.5 40.5 51.5 28 3 5.9

209 Burdur Bayindirlik

ve Iskan Mud.

BRD 37.704 30.221 03.04.2002 37.8128 30.2572 12.5 28.93 21.3 31.25 2 4.4d

210 Andirin Tufan Pasa

Ilkogretim O.

AND 3 7.58 36.34 14.12.2002 37.472 36.221 15.9 76.87 50.42 32.23 1 4.8

211 Akyazi Orman Isl. 40.67 30.622 09.03.2003 40.7328 30.6205 7.0 19.17 23.13 11.63 3 4.3d

212 Bornova Ziraat Fak. Dek. 38.455 27.229 10.04.2003 38.2568 26.8345 40.8 78.58 37.11 17.36 3 5.7

213 Bingol Bayindirlik

ve Iskan Mud.

38.897 40.503 01.05.2003 38.9737 40.534 8.9 152.25 74.62 35.86 2 4.7d

214 Bingol Bayindirlik

ve Iskan Mud.

38.897 40.503 01.05.2003 38.9613 40.341 15.7 19.62 20.23 14.16 2 4.2d

215 Duzce Meteoroloji

Istasyonu

40.844 31.149 21.05.2003 40.87 30.98 14.5 17.82 31.86 16.91 3 4.4

216 Canakkale Meteoroloji Ist. 40.142 26.4 06.07.2003 40.42 26.21 34.8 26.18 15.56 9.12 3 5.8

217 Saraykoy Jeotermal

Lojmanlari

37.932 28.923 23.07.2003 38.1718 28.8533 27.3 90.16 123.23 60.68 3 5.4


ve Isk. Mud.

37.813 29.114 23.07.2003 38.1718 28.8533 45.9 22.19 45.84 19.99 2 5.4


Lojmanlari

37.932 28.923 26.07.2003 38.11 28.88 20.1 47.54 34.46 36.25 3 4.9


Lojmanlari

37.932 28.923 26.07.2003 38.11 28.89 20.0 107.51 121.12 153.97 3 5.5


ve Isk. Mud.

37.813 29.114 26.072003 38.11 28.89 38.4 23.74 25.79 21.67 2 5.5

aConverted from Ms.b Converted from ML.c Converted from Mb.d Converted from Md.



14/27

at Bingol station, which was observed by one of the

authors of this recent study (Aydan et al., 2003), was

also considered.

Some recent attenuation models distinguish be-tween the ground motion from reverse and strike slip

earthquakes with the ground motion from reverse

earthquakes being larger than for strike slip earth-

quakes. Due to the small number of normal faulting

earthquakes in most strong motion data sets, the

difference between ground motions for strike slip

and normal faulting earthquakes has not been included

in most attenuation relations (Douglas, 2003). The

observations performed in the last decade suggested

that even the hypocentral distance is the same; the

acceleration values may be different depending on the

place of the strong ground motion station with respect

to the causative fault and its hanging wall or footwall

(Abrahamson and Somerville, 1996; after Aydan and

Hasgur, 1997). Particularly accelerations recorded at

the stations founded on the hanging wall may be

greater than those obtained from the stations on the

footwall. Although effect of faulting type can be

important, Aydan and Hasgur (1997), who assessed

recorded acceleration values with fault type for some

Turkish earthquakes, indicated that type of faulting

seems to have less influence on the observed PGA

values. These investigators, however, suggested that

this aspect should be further checked in the light of

available data in the future. Gulkan and Kalkan (2002),

who more recently examined the peak ground motiondata from the small number of normal faulting and

reverse faulting earthquakes in the data set of Turkey,

indicated that they were not significantly different

from ground motion characteristics of strike slip char-

acteristics, and normal, reverse or strike slip earth-

quakes could be combined into a single fault category.

It is also noted that focal plane solutions of the most

earthquakes selected from the existing database for this

recent study are not available. Therefore, in this study,

type of faulting was not considered in the development

of the attenuation relationship.

Among all the three-component accessible records,

221 records were selected from 122 earthquakes oc-

curred between 1976 and November 2003 following

the data selection criteria outlined above (PGAz 20

gal, Mwz 4, and 5 km VReV 100 km). The data set

employed in this study is given in Table 1 and distri-

bution of all records with respect to magnitude, dis-

tance to epicenterand site condition is shown in Fig. 4.

Station names in Table 1 are given in Turkish and are

not translated. Based on this set of data, magnitudes of

the earthquakes ranged between 4.1 and 7.5 (Mw).

Fig. 4. The distribution of records in the database employed in this study in terms of magnitude, distance to epicenter and site conditions.



15/27

3. Attenuation relationship development and

comparison with some selected relationships for

PGA

In the development of the attenuation relation-

ship, moment magnitude (Mw), distance to epicenter

(Re), site condition (SA and SB, where SA= SB =0 for

rock sites, SA= 1 and SB = 0 for soil sites, and SA= 0

and SB = 1 for soft soil sites) and recorded largest

horizontal PGA value of each station were employed.

A total of 55 rock sites, 94 soil sites and 72 soft

soil sites were considered in the analyses. In the

first stage of the analyses, one coefficient for each

of these terms was found via multiple regressions,

and an attenuation relationship was derived for

PGA. Then the PGA values predicted from this

relationship and the observed PGA values in the

database were subjected to non-linear regression to

obtain the final attenuation relationship. Based on

the analyses, the following attenuation relationship

was obtained.

PGA 2:18e0:021833:3MwRe7:8427SA18:9282SB 6

The variation of PGA with distance to epicenter for

rock, soil and soft soil sites with respect to different

values of Mw is shown in Fig. 5.

The general performance of the attenuation equa-

tion developed in this study is shown in Fig. 6, where

measured PGA values from the database are plotted

against predicted PGA values using Eq. (6). As seen

from Fig. 6, although a few points fall above and

below the lines with 1:0.5 and 1:2 slopes, which

indicate some overestimates and underestimates, re-

spectively, most of the predictions are scattered withinthese lines. Particularly smaller PGA values fall close

to the line 1:1. Correlation coefficient and standard

deviation corresponding to PGAobserved =PGApredictedcondition are 0.63 and 86.4, respectively.

The PGA values predicted from Eq. (6) were also

compared to those predicted from the domestic and

some imported attenuation relationships. For the pur-

pose, three domestic equations based on Turkish

database and developed by Inan et al. (1996), Aydan

(2001) and Gulkan and Kalkan (2002) were employed.

In the selection of imported equations for comparison,the following criteria were considered: (i) range of

magnitudes employed in derivation of the imported

equations should be similar those employed in this

study, (ii) distance measures employed should be

similar to that used in this study or should be available

from the reports of various institutions, and (iii) the

database employed in derivation of the imported

equations should be collected from the region with

tectonic regimes similar to that in Turkey. Two

imported equations generally satisfying the above-Fig. 5. Curves of PGA versus distance to epicenter for various

magnitudes and different site conditions.

Fig. 6. PGA values predicted from Eq. (6) versus observed PGA

values (r: correlation coefficient; S.D.: standard deviation; n:

number of data).



16/27

mentioned criteria were found in literature. These were

developed by Theodulidis and Papzachos (1992) and

Ambraseys et al. (1996). Theodulidis and Papzachos

(1992) used a database consisting of 105 horizontalcomponents from shallow earthquakes in Greece of

magnitude 4.5 to 7.0, and of 16 horizontal components

from four shallow earthquakes in Japan and Alaska of

magnitudes 7.2 to 7.5. These investigators considered

Ms and Mw, and distance to epicenter as magnitude

scales and distance measure, respectively, and used

two site categories such as alluvium and rock sites.

Ambraseys et al. (1996) used 422 dada from shallow

earthquakes in Europe, Middle East and Turkey. They

considered distance to projection of rupture plane on

surface (Rcl) for the earthquakes with Ms > 6, otherwise

Re as a distance measure. They used four site con-

ditions as rock (1), stiff soil (2), soft soil (3) and very

soft soil (4), but considered only three because only

three records from very soft soil were available.

In order to compare Eq. (6) to the abovementioned

five attenuation relationships main shocks of five

great and one moderate earthquakes of Turkey (1992

Erzincan, 1995 Dinar, 1998 Adana-Ceyhan, 1999

Kocaeli, 1999 Duzce and 2000 Akyazy earthquakes)

with Mw > 6, and a total of three aftershocks from the

1998 Adana-Ceyhan and 1999 Kocaeli earthquakes

with Mw > 5 were selected from Table 1. During thecomparisons the following considerations were made:

(a) Because Aydans equation uses distance to

hypocenter and he preferred to employ focal

depths from ETHZ and if such parameters are not

available, then he utilizes the parameters deter-

mined by USGS or Harvard (Aydan, 2003), in

computations the depths reported by these

institutions were employed. By considering that

Ambraseys et al. (1996) and Gulkan and Kalkan

(2002) employ Rcl as a distance measure, amongthe selected earthquakes mentioned above, only

the earthquakes with known Rcl values, which

have been reported by the institutions were taken

into comparison. However, for some of smaller

events, rupture surfaces have not been defined

clearly, therefore, distances to epicenter were also

used for Gulkan and Kalkans equation when Rclis not available.

(b) Site condition categories 3 and 4 used by

Ambraseys et al. (1996) for soft and very soft

soils were combined into a single group as soft

soil. Because the equations developed by Aydan

(2001) and Theodulidis and Papzachos (1992)

use only two site conditions (rock and soil), in

Fig. 7. Comparison of data from the 1996 Erzincan (a) and 1995

Dinar (b) earthquakes with the curves of the attenuation relation-

ships at soil sites (h: focal depth; Re: distance to epicenter; Rcl:

closest horizontal distance between the recording station and a point

on the horizontal projection of the rupture zone on the earths

surface).



17/27

Fig. 9. Comparison of data from the 1999 Kocaeli earthquake with

the curves of attenuation relationships at rock (a), soil (b) and soft

soil (c) sites.

Fig. 8. Comparison of data from the 1998 Adana-Ceyhan

earthquake at soil (a) and soft soil (b) sites, and the aftershock of

this earthquake at soft soil site (c) with the curves of the attenuation

relationships.



18/27

. .

.

.

.

.

Fig. 10. Comparison of data from two aftershocks (a and b) of the 1999 Kocaeli earthquake with the curves of the attenuation relationships at

rock, soil and soft soil sites.



19/27

this study, both equations were used for the

stations founded on both soil and soft soil sites.

(c) Although type of the magnitude for the equation

developed by Inan et al. (1996) has not beenmentioned in literature, these investigators are

from ERD, which generally reports the earth-

quakes in ML and Md scales. Therefore, one of

these two magnitude scales available was con-

sidered to predict the PGA values from Inan et

al.s equation.

(d) The comparisons for each earthquake with respect

to site conditions were made separately. However,

these equations employed different definitions for

source to site distance. By considering these

differences, x-axis was called source to site

distance (km), and the measured points are shown

by different symbols for Re and Rcl. In other

words, the performance of the equations devel-

oped by Ambraseys et al. (1996) and Gulkan and

Kalkan (2002) was evaluated using Rcl versus

PGA on the plots, which also show the curves of

the other relationships using Re.

The attenuation of PGA for the selected Turkish

earthquakes for rock, soil and soft soil sites are

compared in Figs. 7 12. The observed database

points from these events were also shown on these

Fig. 12. Comparison of data from the 2000 Akyazy earthquake with

the curves of the attenuation relationships at soft soil.

Fig. 11. Comparison of data from the 1999 Du zce earthquake with

the curves of the attenuation relationships at rock (a), soil (b) and

soft soil (c) sites.



20/27

curves to illustrate how well they fit the predictions.

The comparisons indicate that although the attenua-

tion relationships suggested by Inan et al. (1996) and

Theodulidis and Papzachos (1992) show better fits toa few observed data, they generally considerably

overestimates the PGA values for different site con-

ditions. This overestimation becomes more evident

particularly at the near source areas and for big

earthquakes. The second attenuation relationship,

which was used for comparison and developed by

Ambraseys et al. (1996), generally underestimates

the peak acceleration values particularly for some

soil and soft soil sites (Figs. 8b,c, 10bsoil, 11c),

while slightly overestimates for rock sites (Figs. 9a

and 11a). Comparison of the other three relationships

developed using Turkish database (Aydan, 2001;

Gulkan and Kalkan, 2002; this study) suggests that

although many data points fall very close to the

curves representing these relationships, they also

yield some underestimations and overestimations.

Among the equations considered for comparison,

the equations developed in this study and by Aydan

(2001) generally yield similar estimates, which are

closer to the observed PGA values, particularly for

rock sites (Figs. 9a, 10b and 11a). It is also noted

that for soft soil sites during Duzce earthquake

Aydans equation yields a good estimation for Bolustation, while the estimation from the equation de-

veloped in this study is very close to that recorded at

Duzce station. In addition, for this earthquake all

equations compared in this study overestimate the

PGA values for soil sites. Aydan (2003) indicates

that the estimations of the PGA for this earthquake

probably deserve more detailed and sophisticated

functions by considering not only rupture propaga-

tion and ground conditions, but also the topograph-

ical effects.

4. Iso-acceleration map of Turkey

A probabilistic seismic hazard map of Turkey

constructed by Gulkan et al. (1993) replaced seismic

zones in Turkey, and a total of 72 different combina-

tions were used in Bayesian sense to derive a weight-

ed average map corresponding to four different

periods. Then, the seismic hazard zonation map based

on this probabilistic approach was published by the

Ministry of Public Works and Settlement of Turkey

(1996). Based on this map, Turkey is divided into five

subclasses of seismic zone with PGA values of >0.4g,

0.30.4g, 0 .2 0 .3g, 0 .1 0 .2g and < 0.1g ar eassigned for zones ranging from I to V, respectively.

The current practice in Turkey is to directly use the

PGA values from the seismic codes published by the

Ministry of Public Works and Settlement of Turkey

(1998). According to the codes, PGA values of 0.4g,

0.3g, 0.2g and 0.1g are assigned for zones ranging

from I to IV, respectively.

The seismic zoning map of Turkey has some set-

backs and these were outlined by Kayabali and Akin

(2002). In order to minimize the effects of the set-

backs in the present map, new seismic hazard maps

were constructed by Kayabali (2002) and Kayabali

and Akin (2002) using the probabilistic and determin-

istic approaches, respectively. However, Kayabali and

Akin (2002) indicate that the probabilistic-based maps

appear to have employed relatively large seismic

zones, and therefore, deterministic-based seismic

map seems to be more realistic. But in the construc-

tion of the iso-acceleration and seismic hazard maps

of Turkey by Kayabali and Akin (2002), they did not

consider fault segmentation concept and connected

the segments of the main faults of Turkey in their

assessments. In addition, they assumed that a faultwould create a surface rupture equivalent to 1/3 of its

total length and yield the maximum magnitudes.

These assumptions resulted in very long faults, and

consequently very high magnitudes were obtained

when compared to those of the earthquakes associated

with these faults. In this previous study, location of the

epicenters particularly those falling in the areas, where

active faults are not known, were not considered.

Based on the magnitudes estimated, they employed

the attenuation relationship proposed by Sadigh et al.

(1997), who did not account data from normal fault-ing, for the construction of an iso-acceleration and

seismic hazard maps of Turkey. In addition, the PGA

values picked up from the iso-acceleration map con-

structed by these investigators are for bedrock and it is

necessary to carry out site response analyses for the

sites underlain by soil to compute the maximum PGA.

A deterministic based iso-acceleration map of Tur-

key accounting different site conditions and based on

the PGA values derived from the attenuation relation-

ship developed in this study was also constructed. For



21/27

the purpose, the active fault map of Turkey by Saroglu

et al. (1992) was employed as the main material to

define the earthquake sources. In addition, based on

the more recent studies on some active faults, whichhave not been shown on the map by Saroglu et al.

(1992), were also included in the present assessments.

A completed form of the active fault map employed in

this study is shown in Fig. 13a together with the

numbers assigned to the faults. The segments of the

main faults were not connected and each segment was

separately evaluated. Thus a total of 92 main faults (a

total of 141 individual faults) were considered in the

model. Name, length and type of each fault with the

references related to these faults are listed in Table 2.

It is apparent from Fig. 13a, that there are some

regions free from active faults. However, Fig. 13b

indicates the epicenters of a number of earthquakes,

which occurred between 1900 and November 2003,

appear in these regions. This situation suggest that

only the use of distances to the known active faults in

the attenuation relationship will result in unrealistic

PGA assignments for a series of points selected in

such regions. Therefore, in this recent study, the

epicenters were also decided to be used as the second

group of earthquake source.

For fault sources, the magnitude of the upper level

earthquake is usually estimated from fault dimensions.Before fault segmentation concepts were developed,

usually some fraction of the total fault length was used

to estimate the magnitude of the design earthquake.

For example, it was common to use 1/3 to 1/2 of the

total fault length for the estimation of maximum

magnitudes (Mark, 1977). Fault segmentation studies

have replaced this approach for well-studied faults

(Abrahamson, 2000). Therefore, in this study, use of

fault segments is considered to be more realistic in the

prediction of magnitudes, instead of connecting the

segments. For a specific fault, the moment magnitude

of the potential earthquake can be estimated by

relating it to the potential rupture length of the fault

using the relation proposed by Wells and Coppersmith

(1994). However, it was considered that use of a

relationship between magnitude and surface rupture

length based on Turkish earthquake data would be

more realistic. Therefore, the relation proposed by

Aydan (1997) was preferred. This relation is given in

Fig. 13. (a) Active faults compiled from several investigators to be used in this study, and (b) distribution of the epicenters of the earthquakes

occurred in Turkey between 1900 and March 2003.



22/27

Table 2

List of active faults appearing in Fig. 13a and the information

associated with the faults considered in the construction of iso-

acceleration map

Fault

number

Fault name

(segment no.

in Fig. 7a)

Length

(km)

Fault

typeaMaximum

magnitude

(Mw)

assigned

Referenceb

1 NAFZ: Marmara

segment (1-1)

192.3 SS 7.5 2

(1-2) 192.5 SS 7.5 2

(1-3) 60.9 SS 6.6 2

2 NAFZ: Etili Sarikoy

segment (2-1)

60.5 SS 6.6 1

(2-2) 56.1 SS 6.5 1

(2-3) 237.7 SS 7.6 1

3 NAFZ: Yenice

Gonen Bursasegment (3-1)

73.6 SS 6.7 1

(3-2) 108.5 SS 7.0 1

4 NAFZ: Duzce

segment

66.7 SS 6.7 1

5 NAFZ: (5-1) 169.6 SS 7.4 1

(5-2) 98.6 SS 7.0 1

(5-3) 107.0 SS 7.0 1

(5-4) 310.5 SS 7.8 1

(5-5) 154.7 SS 7.3 1

6 Ezinepazari fault 262.5 SS 7.7 1

7 Akpinar Kirsehir

fault zone (7-1)

40.3 SS 6.3 3

(7-2) 23.6 SS 5.9 3

8 Tuzgolu fault zone 187.3 N 7.4 4

9 Gumuskent fault 94.3 SS 6.9 1

10 Ecemis fault zone

(10-1)

97.7 SS 7.0 4

(10-2) 128.2 SS 7.2 4

(10-3) 102.2 SS 7.0 4

(10-4) 55.3 SS 6.5 4

(10-5) 90.1 SS 6.9 4

11 Deliler fault 77.2 SS 6.8 1

12 MalatyaO vacik

fault zone (12-1)

107.5 SS 7.0 1

(12-2) 71.4 SS 6.7 1

(12-3) 64.0 SS 6.6 1

13 Elbistan fault 67.9 SS 6.7 114 Surgu fault 62.3 SS 6.6 1

15 EAFZ (15-1) 269.4 SS 7.7 1

(15-2) 207.4 SS 7.5 1

(15-3) 122.7 SS 7.1 1

16 Kavakbasi fault

(South of Mus)

86.5 SS 6.9 1

17 Mus thrust 88.1 T 6.9 1

18 Bingol Karakocan

fault

51.7 SS 6.5 1

19 Genc fault 26.4 SS 6.0 1

Fault

number

Fault name

(segment no.

in Fig. 7a)

Length

(km)

Fault

typeaMaximum

magnitude

(Mw)

assigned

Referenceb

20 South-East

Anatolian thrust

744.4 T 7.7 1

21 Semdinli Yuksekova

fault zone (21-1)

51.8 SS 6.5 1

(21-2) 47.1 SS 6.4 1

22 NA (22-1) 80.2 SS 6.8 1

Karacadag fault

(22-2)

22.2 U 5.8 1

23 NA (23-1) 18.3 SS 5.7 1

NA (23-2) 42.9 N 6.3 1

24 Bozova fault 51.6 SS 6.5 1

25 Tut fault 25.1 SS 5.9 1

26 Tutak fault (26-1) 108.0 SS 7.0 1Ercis fault (26-2) 33.7 SS 6.1 1

27 Caldiran fault 55.7 SS 6.5 1

28 Hasantimur lake fault 15.6 SS 5.6 1

29 Igdir fault (29-1) 67.9 SS 6.7 1

(29-1) 30.0 SS 6.1 1

30 Balik Golu fault

zone (30-1)

108.7 SS 7.0 1

(30-2) 41.3 SS 6.3 1

(30-3) 39.1 SS 6.3 1

31 Dogubayazit fault 50.8 SS 6.5 1

32 Kagizman fault 90.1 SS 6.9 1

33 Malazgirt fault 21.3 SS 5.8 1

34 Suphan fault 47.0 SS 6.4 1

35 Erzurum fault zone

(35-1)

168.6 SS 7.4 1

(35-2) 169.5 SS 7.4 1

(35-3) 29.7 SS 6.1 1

(35-4) 42.7 SS 6.3 1

(35-5) 57.0 SS 6.5 1

(35-6) 43.4 SS 6.3 1

(35-7) 44.0 SS 6.3 1

(35-8) 40.4 SS 6.3 1

36 KaratasOsmaniye

fault zone (36-1)

59.4 SS 6.6 1

(36-2) 29.9 SS 6.1 1

37 Osun fault 27.1 U 6.0 1

38 Mut fault zone 42.6 U 6.3 139 Karadag fault 23.6 U 5.9 1

40 Sultandagi fault 145.8 N 7.3 1

41 Burdur fault 59.1 N 6.6 1

42 Golhisar-Cameli

fault zone (42-1)

81.7 N 6.8 1

(42-2) 32.0 N 6.1 1

(42-3) 25.4 N 5.9 1

(42-4) 18.1 N 5.7 1

43 Dinar graben (43-1) 17.8 N 5.7 1

(43-2) 19.9 N 5.8 1

Table 2 (continued)



23/27

two forms, as fault rupture length versus Ms (Aydan,

1997) and fault rupture length in logarithmic scale

versus Ms (Aydan et al., 2002). In this study, the latter

relation was employed (Fig. 14). Assuming that each

segment of a main fault and an individual fault would

create a surface rupture equal to its total lengthmeasured from the map shown in Fig. 13a the

maximum magnitudes (Ms) were estimated from Fig.

14 and, then converted to Mw using the equations

found from Fig. 2a (Table 2). However, only the Bitlis

suture zone extending throughout southeastern Ana-

tolia (Fig. 13a) was assumed to cause a surface

rupture equivalent to 1/3 of its total length, when it

is broken (Table 2).

For the construction of the iso-accelaration map of

Turkey, a computer program was written in BASIC

Fault

number

Fault name

(segment no.

in Fig. 7a)

Length

(km)

Fault

typeaMaximum

magnitude

(Mw)

assigned

Referenceb

44 Eskisehir Sultanhani

fault system (44-1)

76.3 N 6.8 5

(44-2) 58.2 N 6.6 5

(44-3) 77.9 N 6.8 5

(44-4) 40.4 N 6.3 5

45 Kaymaz fault 33.1 N 6.1 1

46 Eskisehir fault zone 43.3 N 6.3 1

47 Inonu Dodurga fault

zone (47-1)

77.2 N 6.8 1

(47-2) 38.5 N 6.2 1

48 Kutahya fault 40.3 N 6.3 1

49 Simav fault 56.6 N 6.5 1

50 Akhisar fault 35.3 N 6.2 151 ZeytindagBergama

fault zone

61.8 N 6.6 1

52 Aliaga fault 24.1 N 5.9 1

53 Demirkopru fault

(53-1)

16.7 N 5.6 1

(53-2) 14.1 N 5.5 1

54 Gediz graben (54-1) 130.2 N 7.2 1

(54-2) 168.9 N 7.4 1

55 Buyuk Menderes

graben (55-1)

134.7 N 7.2 1

(55-2) 189.0 N 7.5 1

56 Denizli Honaz fault 61.5 N 6.6 1

57 KaraovaMilas fault

(57-1)

44.6 N 6.4 1

(57-2) 36.9 N 6.2 1

58 Mugla Yatagan fault 46.3 N 6.4 1

59 Ula Oren fault zone 58.3 N 6.6 1

60 Sandikli fault (60-1) 28.5 N 6.0 1

(60-2) 20.9 N 5.8 1

61 Dazkiri .Cardak fault 41.5 N 6.3 1

62 Kas fault 19.8 N 5.7 1

63 Marmaris Koycegiz

fault (63-1)

18.2 N 5.7 1

(63-2) 18.1 N 5.7 1

64 Kumdanli fault 50.2 N 6.4 1

65 Beysehirgolu fault 29.5 N 6.0 1

66 GedizDumlupinarfault (66-1)

33.6 N 6.1 1

(66-2) 46.1 N 6.4 1

67 Sancak Uzunpinar

fault

50.4 SS 6.5 1

68 Merzifon fault 36.4 SS 6.2 1

69 Dodurga fault 19.7 SS 5.7 1

70 Derinkuyu fault 18.2 N 5.7 1

71 Fethiye fault 13.4 U 5.5 1

72 Bala fault 22.7 N 5.9 1

73 Edremit fault 52.3 N 6.5 1

74 NA 45.2 U 6.4 1

Table 2 (continued)

Fault

number

Fault name

(segment no.

in Fig. 7a)

Length

(km)

Fault

typeaMaximum

magnitude

(Mw)

assigned

Referenceb

75 Cildir lake fault 157.1 SS 7.3 1

76 Erivan fault 65.7 SS 6.7 1

77 KarsantiKaraisali

fault zone

65.6 SS 6.7 1

78 Altinekin fault 41.5 N 6.3 5

79 NA 11.2 U 5.3 1

80 NA 13.9 U 5.5 1

81 NA 24.0 SS 5.9 1

82 Trakya fault 102.2 SS 7.0 6

83 NA 17.5 U 5.7 1

84 NA 31.9 U 6.1 1

85 NA 16.5 U 5.6 1

86 NA 17.0 U 5.6 187 Sorgun fault 64.8 SS 6.6 4

88 Sarikaya

Akdagmadeni fault

77.4 SS 6.8 3

89 Delice (Yerkoy) fault 65.9 SS 6.7 3

90 Kirsehir fault 18.8 SS 5.7 3

91 Tatarli fault 48.2 N 6.4 1

92 Acigol fault (92-1) 46.8 N 6.4 1

(93-2) 35.9 N 6.2 1

NAFZ: North Anatolian Fault Zone; EAFZ: East Anatolian Fault

Zone.a SS: Strike slip fault; N: Normal fault; T: Thrust or reverse

fault; U: Although shown on the active fault map of Turkey

(Saroglu et al., 1992), information on fault type is not available.NA: Fault name is not assigned on the available maps.

b 1: Saroglu et al. (1992); 2: Stein et al. (1997); 3:Dirik (1998);

4: Dirik and Goncuoglu (1996); 5: Dirik and Erol (2003); 6: Yaltirak

et al. (1998).

Table 2 (continued)



24/27

programming language. All faults and earthquake

epicenters were identified as a series of points and

as single points with global coordinates, respectively.

Then, the area between the coordinates of 25.545.5j

eastern longitudes and 35.542.5j northern latitudes

was divided by 0.1j intervals and a grid systemcomposed of 14271 points was obtained using the

computer program. The program calculated closest

distances to all faults shown in Fig. 13a and to the

epicenters (Fig 13b) for each grid point. For the

purpose, the points defining each fault zone wereconsidered and the two closest points on each fault

to the grid point under consideration were found.

Then the shortest distance between the grid point

and the fault was calculated. The distances from the

grids to the epicenters were also computed by the

program. The maximum magnitudes assigned to each

fault and/or segment (Table 2) and obtained from the

database for each epicenter were separately employed

in the attenuation relationship (Eq. (6)) suggested in

this study to predict the PGA for each point under

consideration. Then two iso-acceleration maps based

on these two approaches (fault segments and epi-

centers) were constructed. Finally, both maps were

compared by pixel to pixel and the highest of these

PGA values was assigned to each point. Fig. 15 shows

the final iso-accelaration map of Turkey constructed

by following the steps given above. It should be

remembered that the PGA values picked up from this

map is only for rock sites. In order to estimate the

values of PGA for soil and soft soil sites, the picked

up value from the map should be multiplied by 1.186

and 1.511, respectively.

As can be seen from Fig. 15, higher values of PGAare generally concentrated along the main seismotec-

Fig. 14. Relation between surface magnitude (Ms) and surface

rupture length (L) based on the Turkish earthquakes (after Aydan et

al., 2002).

Fig. 15. Base iso-acceleration map of Turkey constructed using the attenuation relationship suggested in this study (PGA contours are in gal and

represent rock sites; for soil and soft soil sites multiple the PGA value picked up from the map by 1.186 and 1.511, respectively).



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tonic features of Turkey. However, in addition to the

faults, the use of the distances to the epicenters, which

has not been considered in construction of the previ-

ous iso-acceleration maps of Turkey, enabled a betterconsideration on the PGA values to represent some

regions far from and/or free from the faults.

5. Conclusions

In this study, an attenuation relationship of PGA

based on the recent Turkish database was presented.

In addition, an attempt was made to construct an iso-

accelaration map using the proposed prediction model

and deterministic approach for Turkey. The proposed

attenuation relationship seems to be helpful for the

prediction of PGA for earthquakes with magnitude

(Mw) ranging between 4.1 and 7.5, and distance to

epicenter equal and/or less than 100 km with respect

to rock, soil and soft soil site conditions.

The comparison between the attenuation relation-

ship suggested in this study and some imported

relations developed using data from Europe and

Middle East indicated that the relationship of Theo-

dulidis and Papzachos (1992) considerably overesti-

mated the PGA values, while Ambraseys et al.s

(1996) equation generally yields underestimated val-ues particularly for soft soil sites. Similarly, the

relationship based on Turkish data and developed by

Inan et al. (1996) yields highly overestimated PGA

values, especially at near source areas. Among the

attenuation relationships used for comparison, the

equations developed for Turkey by Aydan (1997,

2001), Gulkan and Kalkan (2002) and the authors of

this study yield better match with observed data.

Therefore, it can be concluded that the use of atten-

uation relationships based on Turkeys own data

should be preferred to predict more precise PGAvalues.

The suggested iso-acceleration map, which is a

base map considering only rocky ground condition,

was constructed using the PGA values predicted from

a model based on the data from Turkey and also offers

an opportunity to estimate PGA values for soil and

soft soil site conditions when the given coefficients

for these site conditions are multiplied by the PGA

values picked up from the map for a certain point. It is

concluded that the map constructed can be considered

as a base map for a further modification of the

previously suggested seismic hazard zonation map

of Turkey.

Although the attenuation relationship developedin this study and the other two domestic relation-

ships (Aydan, 1997, 2001; Gulkan and Kalkan,

2002) mentioned above predict more precise PGA

values, it is recommended that in order to improve

the precision of the ground motion estimates site

characterization parameters based on shear-wave

velocity measurements at each station, which are

currently lacking in Turkey, need to be included

into the equations. In addition, as recommended by

Aydan and Hasgur (1997) and Aydan (2003) di-

rectivity effect, faulting type and the effect of

overhanging side on footwall should be considered

for when sufficient data on these factors become

available.

Acknowledgements

The authors would like to express their sincere

thanks to Dr. John Douglas and Dr. Mehdi Zare for

their critical reviews and valuable comments that lead

to significant

Attenuation Relationship Based on Turkish Strong Motion Data

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