1. Analysis of regional infrasound signals at IMS infrasound array in Mongolia a RCAG/MAS P.O.B-152, Ulaanbaatar-51Mongolia b CEA/DASE BP12, Bruyeres-le-Chatel, France a RCAG/MAS P.O.B-152, Ulaanbaatar-51 Mongolia (bayarsaikhan@rcag.url.mn)b CEA/DASE BP12, Bruyeres-le-Chatel, France (alexis.le-pichon@cea.fr)(bayarsaikhan@rcag.url.mn)(alexis.le-pichon@cea.fr) a RCAG/MAS P.O.B-152, Ulaanbaatar-51Mongolia b CEA/DASE BP12, Bruyeres-le-Chatel, France a RCAG/MAS P.O.B-152, Ulaanbaatar-51 Mongolia (ulzibat@rcag.url.mn) b CEA/DASE BP12, Bruyeres-le-Chatel, France (Olivier.sebe@cea.fr)(ulzibat@rcag.url.mn)(Olivier.sebe@cea.fr) Infrasound Technology Workshop Tokyo, 13-16 November 2007

2. Content Description of mining explosions around I34MN Seismo-acoustic data analysis: Erdenet Copper mining explosion Baganuur Coal mining explosion Infrasound and seismic signal measurement Data processing and analysis Infrasound wave propagation characteristics Conclusion ITW 2007 Tokyo, 13-16 November 2007

3. Infrasound array Explosion sites and recording stations Mining Seismic array I34MN Ulaanbaatar Erdenet mining Baganuur mining Mining area PS25 ITW 2007 Tokyo, 13-16 November 2007

4. 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 ITW 2007 Tokyo, 13-16 November 2007

5. 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 307 0 -308 0 Baganuur coal mine 93 0 -94 0 ITW 2007 Tokyo, 13-16 November 2007

6. In the Erdenet area, explosions occur once a week on each Friday - Distance relative to the I34MN station ~ 216 km - Scheduled explosions each week at 07-08 UTM - Magnitude range – 2.0 – 2.5 The Baganuur mine makes series of explosions every week - Distance relative to the I34MN station ~ 143 km - Scheduled explosions every week at 02-12 UTM - Magnitude range – 2.0 – 2.5 Characteristics of selected mining areas ITW 2007 Tokyo, 13-16 November 2007

7. 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 ITW 2007 Tokyo, 13-16 November 2007

8. Winter time ( 09 Jan 2004 07:09:33.77 ) Seismic and infrasound recordings from Erdenet copper mine Seismo-acoustic ~11 min ITW 2007 Tokyo, 13-16 November 2007

9. Summer time ( 30 July 2004 05:47:31.27 ) Seismo-acoustic ~11 min ITW 2007 Tokyo, 13-16 November 2007

10. Iw Summer time 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 sec Nb of phase: 2 Examples of PMCC analysis Infrasound recordings I34MN: 216 km Winter time ITW 2007 Tokyo, 13-16 November 2007 Is

11. The detected of winter time (13 Jan 2003 06:30:26.65) Seismic and infrasound recordings Baganuur coal mine Seismo-acoustic ~8 min ITW 2007 Tokyo, 13-16 November 2007

12. The detected of summer time (13 Jan 2003 06:30:26.65) ITW 2007 Tokyo, 13-16 November 2007

13. Winter time Summer time 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 sec Nb of phase: 1 Examples of PMCC analysis Infrasound recordings I34MN: 143 km Iw ITW 2007 Tokyo, 13-16 November 2007

14. 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 ITW 2007 Tokyo, 13-16 November 2007

15. Graphics of travel times Vs azimuth of Erdenet mining explosions ( Red circles are showing - Summer time Blue are winter time) Distribution travel time by azimuth Graphics of travel times Vs azimuth of Baganuur mining explosions ( Red circles are showing - Summer time Blue are winter time) ITW 2007 Tokyo, 13-16 November 2007

16. 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. ITW 2007 Tokyo, 13-16 November 2007 Iw Is

17. CONCLUSION 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. ITW 2007 Tokyo, 13-16 November 2007

18. THANK YOU

22. 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.

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

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

25. 2000-2005

26. 2000-2001

27. 2002-2003

28. 2004-2005