Analysis of regional infrasound signals at IMS infrasound array in Mongolia

Analysis of regional infrasound signals at IMS infrasound array in

Mongolia

a RCAG/MAS P.O.B-152, Ulaanbaatar-51a RCAG/MAS P.O.B-152, Ulaanbaatar-51 Mongolia Mongolia (([email protected]@rcag.url.mn))b b CEA/DASE BP12, Bruyeres-le-Chatel, France CEA/DASE BP12, Bruyeres-le-Chatel, France (([email protected]@cea.fr))a RCAG/MAS P.O.B-152, Ulaanbaatar-51a RCAG/MAS P.O.B-152, Ulaanbaatar-51 MongoliaMongolia ([email protected]) b b CEA/DASE BP12, Bruyeres-le-Chatel, France CEA/DASE BP12, Bruyeres-le-Chatel, France (([email protected]@cea.fr))

Infrasound Technology Workshop Tokyo, 13-16 November 2007

mailto:[email protected]












Content

Description of mining explosions around I34MN

Seismo-acoustic data analysis:

Erdenet Copper mining explosionBaganuur Coal mining explosion

Infrasound and seismic signal measurement

Data processing and analysis

Infrasound wave propagation characteristics

Conclusion

ITW 2007 Tokyo, 13-16 November 2007

Infrasound array

Explosion sites and recording stations

Mining Seismic array

I34MN

Ulaanbaatar

Erdenetmining

Baganuurmining

Mining area

Mining area

PS25


Detected by seismic station

1085 Baganuur

184 Boroo758 Sharyn gol

343 Shivee 260 Erdenet

Detected by Infrasound station

352 Baganuur 50 Boroo

70 Sharyn gol33 Shivee

114 Erdenet

Recorded at seismic PS25 stations and

analyzed by seismic data

Statistics analysis of quarry blast

Detected mining explosions between 2000 and 2005

Recorded at infrasound I34MN stations and analyzed by PMCC automatic bulletin


All detected infrasound signals as a function of time and azimuth

(left histogram shows number of detected events)

Detected infrasonic signals between 2000-2005

Erdenet copper mine

3070-3080

Baganuur coal mine

930-940


In the Erdenet area, explosions occur once a week on each In the Erdenet area, explosions occur once a week on each FridayFriday - Distance relative to the I34MN station ~- Distance relative to the I34MN station ~ 216 km 216 km - Scheduled explosions each week at 07-08 UTM - Scheduled explosions each week at 07-08 UTM

- Magnitude range – 2.0 – 2.5- Magnitude range – 2.0 – 2.5

The Baganuur mine makes series of explosions The Baganuur mine makes series of explosions every weekevery week- - Distance relative to the I34MN station ~Distance relative to the I34MN station ~ 143 km 143 km

- Scheduled explosions every week at 02-12 UTM - Scheduled explosions every week at 02-12 UTM - Magnitude range – 2.0 – 2.5- Magnitude range – 2.0 – 2.5

Characteristics of selected mining areas


Relocation results: explosions from the Baganuur and Erdenet mining sites were reviewed and relocated by combination of seismic and infrasound phase arrivals.

Relocated events, an input for a new interpretation


Winter time (09 Jan 2004 07:09:33.77 )

Seismic and infrasound recordings from Erdenet copper mine

Seismo-acoustic ~11 min


Summer time (30 July 2004 05:47:31.27 )



Iw

Iw

Sum

mer

tim

e

Detailed processing of data is done manually using PMCC

results of Erdenet

Displays the distribution of detection according in a Speed/Back Azimuths

radar plot (Erdenet)

Duration: 32 secNb of phase: 2

Examples of PMCC analysis Infrasound recordings

I34MN: 216 km

Win

ter

time


Is

The detected of winter time (13 Jan 2003 06:30:26.65)

Seismic and infrasound recordings Baganuur coal mine



The detected of summer time (13 Jan 2003 06:30:26.65)


Win

ter

time

Sum

mer

tim

e

Displays the distribution of detection according in a Speed/Back Azimuths

radar plot (Baganuur)

Detailed processing of data is done manually using PMCC

results of Baganuur

Duration: 30 secNb of phase: 1

Examples of PMCC analysis Infrasound recordings

I34MN: 143 km

Iw

Iw


Number of quarry blast used for analysis Travel time distribution by distance, red circles correspond to Baganuur and blue

circles are Erdenet

SEISMO-ACOUSTIC DATA ANALYSIS


Graphics of travel times Vs azimuthof Erdenet mining explosions

( Red circles are showing - Summer time

Blue are winter time)

Distribution travel time by azimuth

Graphics of travel times Vs azimuthof Baganuur mining explosions

( Red circles are showing - Summer time

Blue are winter time)


Distribution of travel time by Julian date, red circle are Baganuur explosion and black circle are

Erdenet

Distribution of celerity by month, green and blue dot are manual

measurement data of Baganuur and Erdenet, pink and red squares are

mean of all data

We compared all manual measurements of infrasound data from Erdenet and Baganuur mining sites by month and by travel time and date. The observed variation of about 100 seconds is mainly due to seasonal dependence of atmospheric wind characteristics.


Iw

Is

Is

CONCLUSIONCONCLUSION

Many seismic and infrasonic signals are observed daily. Nearly a quarter of all seismic signals has associated infrasonic arrivals. Most of them occur during local working hours. These observations suggest that a great deal of the activity observed is man-made. Many of the seismo-acoustic signals are located in the distance range of 40 to 500 km from the IS34MN array. The efficiency of the detection of these man-made seismo-acoustic events is largely dependent on the regional infrasound propagation conditions related to the sound velocity, the epicentral as well as the wind force and direction.

Additional work is needed in the interpretation and modeling of seismic and infrasound signals.


THANK YOU

Conclusion

The seasonal dependence of travel time is mainly controlled by seasonal variations of atmospheric wind force and direction. The seasonal temperature variation has almost no effect.

Infrasound –ûí í¿¿äëèéí ñòàíöûã áîãèíî õóãàöààãààð ñóóðèëëóóëààä source-óóäûã òîäîðõîéëîõ áîëîìæûí òàëààð (determine source of detection natural and some noise

Question

Continues work data analysis Ýäãýýð ¿ð ä¿íãýýð….

2000-2005

2000-2001

2002-2003

2004-2005

Analysis of regional infrasound signals at IMS infrasound array in Mongolia

Documents

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