Information message about sensitive earthquake in Azerbaijan on May 7, 2012 |
| The sensitive earthquake with M=5.8 has occurred in Azerbaijan on May 7, 2012 at 04:40 GMT (08:40 Moscow time). |
| 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 12 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 87 stations, accurate processing - with data 89 stations. |
| Fig. 1 presents fragments of records obtained from digital stations Akhty (∆ 0.7º), Botlikh (∆ 1.2º), Garni (∆ 2.2º), Nalchik (∆ 3.1º), Kislovodsk (∆ 3.9º). Fig. 2 presents fragments of records obtained from digital stations Obninsk (∆ 15.1º), Kiev (∆ 15.2º), Arti (∆ 16.7º), Borovoe (∆ 19.5º), Lovozero (∆ 27.2º). |
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 |
04-40-25.9 |
41.56 |
46.88 |
10 |
89 |
5.8/27 | 5.8/29 | 7-8 | 47 | IPC GS RAS (Accurate) | | 2 |
04-40-25.9 |
41.55 |
46.9 |
10 |
87 |
5.8/24 | 5.8/24 | 7-8 | 47 | IPC GS RAS (Preliminary) | | 3 |
04-40-27.6 |
41.5 |
46.67 |
10 |
28 |
Mw 5.6 | | | 103 | CSEM | | 4 |
04-40-29.6 |
41.54 |
46.77 |
23.3 |
150 |
| 5.6 | | 29 | NEIC | | 5 |
04-40-30.0 |
41.18 |
46.77 |
14 |
13 |
| 5.8 | | 261 | IGUT | | 6 |
04-40-18.6 |
41.27 |
46.98 |
1 |
|
ML 5.7 | | | | UNSSPG | | 7 |
04-40-25.4 |
41.5 |
46.67 |
10 |
27 |
ML 5.6 | | | 101 | RSSC | |
| 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 |
| IGUT - Institute of Geophysics, University of Tehran |
| UNSSPG - United National Survey for Seismic Protection , Georgia |
| RSSC - Republican Seismic Survey Center of Azerbaijan National Academy of Sciences |
| Epicenter |
| Fig. 3 presents with red star epicenter of this earthquake, it’s origin was located on the territory of Azerbaijan at the depth of 10 km, 17 km N-N-W of Kakhi, Azerbaijan, 21 km E-S-E of Zaqatala, Azerbaijan, 62 km E of Dedoplis-Tskaro, Georgia, 74 km W of Akhty, Russia, and 74 km N-E of Tlyarata, Russia. |
Figure 3 |
|
| Aftershock |
| GS RAS registered 17 aftershocks with M>3.5 within 20 hours after the main shock.
Aftershock at 05:38 was felt in Akhty with intensity 2-3 MSK.
Aftershock at 05:38 was felt in Akhty with intensity 4 MSK, in Rutula with intensity 3 MSK. |
| N |
Date & Time (GMT)
yy-mm-dd hh:mm:sec |
Lat
degr. |
Lon
degr. |
Depth
km |
N
station |
Ms/ N |
mb/ N |
Io
calc. |
Region |
| 20121847 | 2012-05-07 05:08:31.0 | 41.5 | 46.75 | 10 | 9 | - | 4.0/ 3 | 3 | Eastern Caucasus | | 20121848 | 2012-05-07 05:27:06.0 | 41.56 | 46.84 | 10 | 10 | - | 3.8/ 2 | 2.5-3 | Eastern Caucasus | | 20121849 | 2012-05-07 05:38:02.0 | 41.44 | 46.86 | 10 | 51 | - | 4.7/ 20 | 4.5-5 | Eastern Caucasus | | 20121850 | 2012-05-07 05:40:29.0 | 41.33 | 46.86 | 10 | 30 | - | 4.4/ 9 | 4 | Eastern Caucasus | | 20121853 | 2012-05-07 08:27:38.0 | 41.45 | 46.87 | 10 | 21 | - | 3.7/ 6 | 2-2.5 | Eastern Caucasus | | 20121855 | 2012-05-07 08:36:22.0 | 41.41 | 46.92 | 10 | 31 | - | 4.3/ 8 | 3.5-4 | Eastern Caucasus | | 20121854 | 2012-05-07 14:15:12.0 | 41.53 | 46.85 | 10 | 75 | 5.0/ 28 | 5.6/ 21 | 7 | Eastern Caucasus | | 20121856 | 2012-05-07 14:36:20.0 | 41.39 | 46.9 | 10 | 19 | - | 4.0/ 4 | 3 | Eastern Caucasus | | 20121857 | 2012-05-07 14:51:28.0 | 41.35 | 46.82 | 10 | 28 | - | 4.0/ 5 | 3 | Eastern Caucasus | | 20121859 | 2012-05-07 15:48:07.0 | 41.43 | 46.98 | 10 | 16 | - | 3.7/ 2 | 2-2.5 | Eastern Caucasus | | 20121860 | 2012-05-07 16:58:56.0 | 41.54 | 46.83 | 10 | 37 | - | 4.6/ 10 | 4.5 | Eastern Caucasus | | 20121861 | 2012-05-07 17:04:31.0 | 41.48 | 46.85 | 10 | 13 | - | 3.9/ 3 | 2.5-3 | Eastern Caucasus | | 20121862 | 2012-05-07 17:08:08.0 | 41.46 | 46.81 | 10 | 10 | - | 3.7/ 2 | 2-2.5 | Eastern Caucasus | | 20121864 | 2012-05-07 17:49:44.0 | 41.51 | 46.83 | 10 | 8 | - | 3.6/ 1 | 2-2.5 | Eastern Caucasus | | 20121865 | 2012-05-07 18:18:46.0 | 41.44 | 46.89 | 10 | 15 | - | 3.8/ 4 | 2.5-3 | Eastern Caucasus | | 20121866 | 2012-05-07 18:49:36.0 | 41.54 | 46.88 | 10 | 14 | - | 3.8/ 4 | 2.5-3 | Eastern Caucasus | | 20121871 | 2012-05-08 00:06:38.0 | 41.52 | 46.96 | 10 | 16 | - | 3.8/ 2 | 2.5-3 | Eastern Caucasus | |
| Macroseismic manifestations |
| In accordance with RIA-Novosti this earthquake was felt in Zaqatala and Qakh Rayons with intensity 7 MSK, in Shaki, Oghuz, Qazahk, Tovuz and some other Rayons with intensity from 2 to 5 MSK.
In Zaqatala Rayon 15 persons asked for minor medical help, no seriously injured people were registered. After this earthquake some houses in settlements were damaged, most of all this was observed in Azar, Zayam and Gymyr villages. Besides that there were found cracks in walls and roof damages in many private living houses and high buildings in regional center as well as in villages.
In accordance with GS RAS this earthquake was felt on the territory of Russian Federation in Tlyarata with intensity 6 MSK, in Shamilkala, Hunzakh, Akhty, Bujnaksk with intensity 5 and in Makhachkala with intensity 4 MSK.
|
| Focal mechanism and seismic moment of the earthquake |
| Focal mechanism of the earthquake occurred on May 7, 2012 at 04h 40m was computed in the IPC GS RAS by signs of first-motion in P-wave at 138 stations, including 114 stations which registered compression waves ("plus" signs) and 24 stations with registered extension waves ("minus" signs). The stations are located within 0.6º-100º range of epicentral distances, uniformly by azimuth. The focal mechanism in stereographic projection on lower hemisphere is shown in Figure 4, its elements are presented in Table 2. Also the fault-plane solutions computed by WPhase Moment Solution method at the National Earthquake Information Center of the U.S. Geological Survey (USGS NEIC) and by centroid moment tensor method in the Quick CMT Catalog, United States, are shown in Table 2 and Fig.5, 6. The solutions of all centres are similar. The earthquake occurred under the action of identical by value compression and tension stresses oriented to the south-southwest and north-northeast respectively. The strike of NP1 nodal plane is north-west with north-east dipping according to the IPC GS RAS and the Quick CMT, or east-west strike with north dipping according to the NEIC solution; type of movement on NP1 plane is a low-angle thrust. The steeply dipping NP2 plane has a south-eastern strike and south-west dipping, the type of movement on it is a reverse fault. Seismic moment of the earthquake determined in the IPC GS RAS from P-wave spectrum at the "Talaya" station (Δ 39.37º) is Mo = 1.5*10**18 Nm. The average value of moment magnitude Mw calculated in the IPC GS RAS using Kanamori formula is Mw=6.1. According to the USGS NEIC, Mo=3.5*10**17 Nm, Mw=5.7, according to the Quick CMT, Mo=4.37*10**17 Nm, Mw=5.7. |
| 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 |
| 51 | 20 | 38 | 210 |
5 | 116 | 332 | 8 | 126 | 116 |
84 | 85 | IPC GS RAS | | 58 | 37 | 30 | 201 |
7 | 296 | 271 | 16 | 64 | 118 |
76 | 97 | NEIC | | 57 | 15 | 33 | 200 |
2 | 109 | 300 | 12 | 102 | 108 |
78 | 87 | 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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