Geographical distribution of important earthquakes.pptx

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Geographical distribution of

important earthquakes



Earthquake Zones

Plate margins are the major sites of theearthquakes, but they also can occur within a

plate.

Three types of plate margins are:1. Convergent boundaries

2. Divergent boundaries

3. Transcurrent boundaries



• Earthquakes occur mainly:

– Along trenches (subduction zones),

– Along ridge-transform systems,

– In continental interiors.



• The world largest earthquakes occur alongsubduction zones (e.g., the 1960 Chilean

earthquake, M=9.5, the 1964 Alaskanearthquake, M=9.2).

• More than 75 % of the seismic energy release

takes place there.• Most of these events represent slip on the

interface between a subducting oceanic plateand an overriding plate.

• In these zones deep focus earthquakes occurto a depth of about 700 km.



• Most earthquakes along ridge-transformsystems are shallow and relatively small (10%in energy release).

• The events on ridges have normal-faultmechanism, and those along the transform

boundaries have strike-slip mechanisms.• Transform fault events are generally larger;

occasionally the magnitude reaches 8 (e.g.,

the 1906 San Francisco earthquake, M≅

8 ).• No deep focus earthquake has been found

beneath ridge-transform systems.



• The interplate earthquakes in collision zones

are usually shallow (<100 km), and dominated

by low angle thrusting, which is amanifestation of lithospheric shortening.

• The distribution of the events in continental

interiors (15 % in energy release) is verydiffuse.

• Partly because of their proximity to major

population centers, large intra continentalevents are often very devastating.



Earthquake Density Maps for the World



Number of Earthquakes Worldwide

2000 - 2012

Magnitude 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

8.0 to 9.9 1 1 0 1 2 1 2 4 0 1 1 1 2

7.0 to 7.9 14 15 13 14 14 10 9 14 12 16 23 19 5

6.0 to 6.9 146 121 127 140 141 140 142 178 168 144 151 185 52

5.0 to 5.9 1344 1224 1201 1203 1515 1693 1712 2074 1768 1896 2104 2276 689

4.0 to 4.9 8008 7991 8541 8462 10888 13917 12838 12078 12291 6805 10267 13315 3987

3.0 to 3.9 4827 6266 7068 7624 7932 9191 9990 9889 11735 2905 4329 2791 706

2.0 to 2.9 3765 4164 6419 7727 6316 4636 4027 3597 3860 3014 4624 3643 980

1.0 to 1.9 1026 944 1137 2506 1344 26 18 42 21 26 39 47 19

0.1 to 0.9 5 1 10 134 103 0 2 2 0 1 0 1 0

No Magnitude 3120 2807 2938 3608 2939 864 828 1807 1922 17 24 11 7

Total 22256 23534 27454 31419 31194 30478 29568 29685 31777 * 14825 * 21562 * 22289 * 6447

Estimated

Deaths 231 21357 1685 33819 228802 88003 6605 712 88011 1790 320120 21953 131



Largest Earthquakes in the World

Since 1900



Location Date UTC Magnitude Lat. Long. Reference

1. Chile 1960 05 22 9.5 -38.29 -73.05 Kanamori, 1977

2. Prince William Sound, Alaska 1964 03 28 9.2 61.02 -147.65 Kanamori, 1977

3. Off the West Coast of Northern

Sumatra

2004 12 26 9.1 3.30 95.78 Park et al.,

2005

4. Near the East Coast of Honshu,Japan

2011 03 11 9.0 38.322 142.369 PDE

5. Kamchatka 1952 11 04 9.0 52.76 160.06 Kanamori, 1977

6. Offshore Maule, Chile 2010 02 27 8.8 -35.846 -72.719 PDE

7. Off the Coast of Ecuador 1906 01 31 8.8 1.0 -81.5 Kanamori, 1977

8. Rat Islands, Alaska 1965 02 04 8.7 51.21 178.50 Kanamori, 1977

9. Northern Sumatra, Indonesia 2005 03 28 8.6 2.08 97.01 PDE

10. Assam - Tibet 1950 08 15 8.6 28.5 96.5 Kanamori, 1977

11. Off the west coast of northern

Sumatra

2012 04 11 8.6 2.311 93.063 PDE

12. Andreanof Islands, Alaska 1957 03 09 8.6 51.56 -175.39 Johnson et al.,

199413. Southern Sumatra, Indonesia 2007 09 12 8.5 -4.438 101.367 PDE

14. Banda Sea, Indonesia 1938 02 01 8.5 -5.05 131.62 Okal and

Reymond, 2003

15. Kamchatka 1923 02 03 8.5 54.0 161.0 Kanamori, 1988

16. Chile-Argentina Border 1922 11 11 8.5 -28.55 -70.50 Kanamori, 1977

17. Kuril Islands 1963 10 13 8.5 44.9 149.6 Kanamori, 1977

Updated 2012 April 11



Geographical distribution of

earthquakes in Pakistan

• For earthquake hazard study, Pakistan is dividedinto nineteen zones including some portions of the neighboring countries of Afghanistan,

Tajikistan, Iran and India.• Pakistan is located on the north-west region of

the Indian plate that pushes into the Eurasianplate.

• The division of the region into these source zonesis based on the seismicity, the fault systems andthe stress direction analysis.



• Zone 1; Kohistan-Kashmir

• Zone 2; Northern Baluchistan

•Zone 3; Quetta-Sibi

• Zone 4; Southern Baluchistan

• Zone 5; Northern Afghanistan-Tajikistan

•Zone 6; Hindu Kush

• Zone 7; North Western Afghanistan-TajikistanBorder Region

•

Zone 8; Eastern Afghanistan• Zone 9; Makran Coast

• Zone 10; Runn of Kuchch



• Zone 11; Sindh-Punjab

• Zone-12; Pamir-Kunlun

• Zone 13; Indian Kashmir

• Zone 14; Upper Punjab-NWFP

•Zone 15; Chitral

• Zone 16; Koh e Sulaiman

• Zone 17; South West Iran

• Zone 18; Western Baluchistan

• Zone 19; Central & Southern Afghanistan



Zones of high seismic activity in

Pakistan

• It was observed that most of the large

earthquakes occurred in the following regions:

– Hindu Kush region

– Northern areas of Pakistan and Kashmir

– North-western part of Baluchistan and

– The coastal areas of Pakistan (near Makran region)

– The south-eastern corner of Pakistan (Runn of Kutch)


http://slidepdf.com/reader/full/geographical-distribution-of-important-earthquakespptx 18/22Seismicity of the region



SeismicHazard

Map

h k



Earthquake

Density Map



Seismicity Map

1900 to Present



Historic Earthquakes in Pakistan

•

1935/05/30 - Quetta, Pakistan - M7.5 Fatalities 30,000

• 1945/11/27 - Makran Coast, Pakistan - M

8.0 Fatalities 4,000• 1974/12/28 - Northern Pakistan - M

6.2 Fatalities 5,300

•

2005/10/08 –

Muzaffarabad Pakistan - M7.6 Fatalities 86,000

• 2008/10/28 – Balochistan, Pakistan - M

6 4 Fatalities 166

Geographical distribution of important earthquakes.pptx

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