Information message about the strong earthquake in Kyrgyzstan on July 19, 2011. |
| The strong earthquake with M=6.3 which caused victims and destructions has occurred on July 19, 2011 at 19:35 GMT (23:35 Moscow time) at the border area between Kyrgyzstan Uzbekistan and Tajikistan. |
| Parameters of the earthquake
have been determined in the Alert Service (AS) of Information
Processing Center (IPC) of Geophysical Survey of RAS in Obninsk with station data
obtained from digital and analog seismic stations of Russia, countries of CIS
and from abroad. Alert message on this earthquake has been delivered in 17 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 55 stations, accurate processing - with data 62 stations. |
| Fig. 1 presents fragments of records obtained from digital stations Ala Archa (∆ 3.4º), Kurchatov (∆ 11.8º), Borovoe (∆ 13º), Arti (∆ 18.4º), Kislovodsk (∆ 21.6º). Fig. 2 presents fragments of records obtained from digital stations Storozhevoe (∆ 24.9º), Talaya (∆ 25.1º), Obninsk (∆ 27.5º), Kiev (∆ 31º), Kaliningrad (∆ 36.7º). |
Figure 1
| 
Figure 2
|
|
| IPC GS RAS also has obtained information with parameters of this event from some seismological centers, these data are given in table 1: |
| Table 1 |
| NN |
Time in origin h-min-s (GMT) |
Lat degr. |
Lon degr. |
Depth km |
N s/st |
Ms/ N |
mb/ N |
I0 calc |
GAP |
Center | | 1 |
19-35-40.3 |
40.12 |
71.37 |
10 |
62 |
6.3/25 | 6.3/21 | 8.5-9 | 43 | IPC GS RAS (Accurate) | | 2 |
19-35-40.3 |
40.11 |
71.35 |
10 |
55 |
6.3/19 | 6.3/18 | 8.5-9 | 43 | IPC GS RAS (Preliminary) | | 3 |
19-35-42.2 |
40.12 |
71.46 |
10 |
788 |
6.1Mw | | | 19 | CSEM | | 4 |
19-35-43.2 |
40.15 |
71.43 |
16 |
437 |
6.3/491 | 6.1/295 | | 14 | NEIC | | 5 |
19-35-40.0 |
40.19 |
71.38 |
0 |
30 |
К14.3 | 6.2/16 | | 21 | KNDC | |
| IPC GS RAS - Informational Processing Center, Geophysical Survey, Russian Academy of Sciences |
| CSEM - European - Mediterranean seismological center |
| NEIC - National Earthquakes Information Center of US Geological Service |
| KNDC - Kazakhstan National Data Center |
| Epicenter |
| Fig.3 presents epicenter of this earthquake which origin was located in Kyrgyzstan, this is the border area between Kyrgyzstan-Uzbekistan-Tajikistan, at the depth of 10 km, 40 km S-W of Farghona, 225 km S-E of Tashkent and 280 km N-E of Dushanbe. |
Figure 3 |
|
| Macroseismic manifestations |
| «In course of the earthquake some living houses were damages in Rishtansk, Bagdad and Uzbekistan areas of Ferghona region. As a result 13 people were killed, 86 people required ambulance aid and 35 of them were transported to hospital», – this is the message of Uzbekistan EMERCOM, which was cited by «Interfax» news agency.
The earthquake was felt in Kyrgyzstan: Sovetsk with intensity - 7-8, Batken - 6, Osh - 5, Bishkek - 2-3; in Uzbekistan: Tashkent and Farghona – 5, Termez - 4, Samarkand - 3; in Tajikistan: Dushanbe - 3; in Kazakhstan: Shymkent – 3-4, Taraz – 3, Alma Aty - 2.
Fig. 4 present the map of intensities obtained from NEIC USA (46 responses in 11 cities). |
Figure 4 |
|
| Focal mechanism and seismic moment of the earthquake |
| Focal mechanism solution of the origin for the earthquake which occurred on July 19, 2011 at 19:35 GMT was calculated in IPC GS RAS with signs of initial arrivals of P waves at 111 stations, including 98 stations which registered the waves of compression (plus signs), and 13 stations which registered the waves of expansion (minus signs). These stations are located uniformly with interval of epicenter distances of 0º-92º along the azimuth. Focal mechanism solution in stereographic projection at the lower hemisphere is presented in figure 5, element of this solution are presented in table 2. Figures 6, 7 and table 2 present focal mechanism solution of the origin, which was calculated with method of tensor based on long period phases in NEIC USA, USGS and with CMT technique in the Global CMT Catalog, USA.
All solutions are almost identical. This earthquake has occurred under the action of compression forces oriented to the north. Both nodal planes have near along latitude direction of propagation, one of them NP1 lays flat (DP=26-34º), the type of motion along it – thrust with left side shift component, another plane NP2 is steeply falling (DP=58-66º), the type of motion along it – uplift with right side shift component.
Seismic moment obtained in IPC GS RAS with spectra of Р-waves at three stations: «Arti» (∆ 18.36º), «Kislovodsk» (∆ 21.59º), «Obninsk» (∆ 27.48º) makes Mo=1.1* 10** 17 n*m. Averaged value of moment magnitude Mw was calculated with Kanamori formula and makes Mw=6.0.
According to USGS - Мо=1.5*10**18 n*m, Mw=6.1; according to Global CMT – Мо=1.86*10**18 n*m, Mw=6.1. |
| Table 2 |
| Axes of main strengths |
Nodal planes |
Center |
| T |
P |
N |
NP1 |
NP2 |
| Pl |
Azm |
Pl |
Azm |
Pl |
Azm |
Stk |
Dp |
Slip |
Stk |
Dp |
Slip |
| 73 | 200 | 13 | 339 |
11 | 72 | 55 | 34 | 71 | 258 |
58 | 102 | IPC GS RAS | | 74 | 190 | 15 | 358 |
3 | 89 | 84 | 30 | 84 | 271 |
61 | 94 | NEIC | | 67 | 199 | 21 | 352 |
10 | 86 | 65 | 26 | 67 | 270 |
66 | 100 | Quick CMT | |
| IPC GS RAS - Informational Processing Center, Geophysical Survey, Russian Academy of Sciences |
| NEIC - National Earthquakes Information Center of US Geological Service |
| Quick CMT - Quick CMT catalog |
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