Information message about destructive earthqauke in Turkey on October 23, 2011 |
| Significant earthquake with М=7.4, which caused victims and destructions has occurred in Turkey on October 23, 2011 at 10:41 GMT (14:41 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 15 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 65 stations. |
| Fig. 1 presents fragments of records obtained from digital stations Neitrino (∆ 4.6), Kislovodsk (∆ 5.4º), Kiev (∆ 15.7º), Obninsk (∆ 17.1º), Arti (∆ 20.5º). Fig. 2 presents fragments of records obtained from digital stations Borovoe (∆ 23.5º), Lovozero (∆ 29.7º), Talaya (∆ 43.3º), Tiksi (∆ 52.5º), Yakutsk (∆ 55.1º). |
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 |
10-41-20.5 |
38.62 |
43.39 |
15 |
65 |
7.4/25 | 7.1/18 | 9.5-10 | 91 | IPC GS RAS (Accurate) | | 2 |
10-41-19.9 |
38.55 |
43.32 |
15 |
55 |
7.4/23 | 7.1/16 | 9.5-10 | 160 | IPC GS RAS (Preliminary) | | 3 |
10-41-22.7 |
38.859 |
43.477 |
10 |
280 |
Mw 7.3 | | | 42 | CSEM | | 4 |
10-41-21.0 |
38.628 |
43.486 |
20 |
|
Mw 7.2 | | | | NEIC | | 5 |
10-41-21.8 |
38.723 |
43.436 |
4.9 |
29 |
ML 6.6 | | | | KOERI | |
| 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 |
| KOERI - Kandilli Observatory and Earthquake Research Institute, Turkey |
| Epicenter |
| Fig.3 presents with red star epicenter of this earthquake which origin was located in the eastern part of Turkey, in province Kütahya, at the depth of 15 km, 14 km N-N-W of Van, 114 km E-N-E of Bitlis and 203 km S-W of Armenian capital Erevan. |
Figure 3 |
|
| Aftershock |
| GS RAS registered 27 aftershocks with М>4.5 in within one day after the main shock. The table here presents 11 of them being most significant with М>=5. |
| 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 |
| 20114421 | 2011-10-23 10:56:46.0 | 38.57 | 43.1 | 20 | 31 | - | 5.9/ 15 | 6.5 | Turkey | | 20114422 | 2011-10-23 11:00:28.0 | 38.37 | 43.16 | 20 | 22 | - | 5.6/ 7 | 5.5-6 | Turkey | | 20114423 | 2011-10-23 11:10:49.0 | 38.32 | 43.1 | 10 | 19 | - | 5.3/ 5 | 6-6.5 | Turkey | | 20114424 | 2011-10-23 11:32:39.0 | 38.69 | 43.36 | 20 | 41 | - | 5.8/ 12 | 6-6.5 | Turkey | | 20114429 | 2011-10-23 15:24:29.0 | 38.35 | 43.13 | 15 | 27 | - | 5.1/ 12 | 5 | Turkey | | 20114432 | 2011-10-23 18:10:46.0 | 38.57 | 43.31 | 15 | 28 | - | 5.3/ 11 | 5.5 | Turkey | | 20114435 | 2011-10-23 18:53:46.0 | 38.53 | 43.29 | 15 | 24 | - | 5.1/ 8 | 5 | Turkey | | 20114436 | 2011-10-23 19:06:06.0 | 38.78 | 43.21 | 15 | 25 | - | 5.1/ 11 | 5 | Turkey | | 20114433 | 2011-10-23 20:45:37.0 | 38.68 | 43.19 | 15 | 35 | - | 6.2/ 15 | 7.5-8 | Turkey | | 20114439 | 2011-10-23 22:21:30.0 | 38.48 | 43.07 | 15 | 14 | - | 5.0/ 5 | 4.5-5 | Turkey | | 20114448 | 2011-10-24 08:49:20.0 | 38.83 | 43.5 | 15 | 30 | - | 5.0/ 17 | 4.5-5 | Turkey | |
| Macroseismic manifestations |
| According to RIA-Novosti number of earthquake victims in the Turkish province of Van, as of Friday morning had risen to 570, 2555 people were injured. As a result, the largest in recent years, the disaster in Turkey destroyed about three thousand houses.
Fig. 4 published at WEB site of NEIC USGS , presents Community Internet Intensity Map. |
Figure 4 |
|
| Historical records |
| Turkey is located in seismic active region being the place of numerous destructive earthquakes. Epicenter of the earthquake reported here is located in the zone of interaction between Arabian and Eurasian plates. It reminds about numerous catastrophic events, which happened in Turkey in the recent past. These are the earthquake in Erzincan in 1939 with M=7.8, which killed approximately 33 000 people. Consequences of another earthquake happened in Eastern Anatolia near lake Van in 1976 with М=7.3 were some destroyed villages near Turkey-Iran border and a few thousand fatalities. It was destructive Izmir earthquake on August 17, 1999 with М = 7.6, which killed 17 000, injured 50 000 and left without home 500 000 people. |
| Focal mechanism and seismic moment of the earthquake |
| Fault-plane solution of the earthquake occurred on October 23, 2011 at 10h41m (GMT) was found in the IPC GS RAS by direction of first motion of P wave onsets on seismic records of 295 stations, of which 290 recorded a compression wave (“+” sign) and 5 – an dilatation wave (“–“). The stations are located uniformly by azimuth (1º – 360º) in the range of epicentral distances from 1º to 94º. Focal mechanism in the stereographic projection on lower hemisphere is shown in Figure 5, its elements are presented in Table.2. Also the focal mechanism solution calculated by the National Earthquake Information Center (NEIC) of US Geological Survey (USGS) using moment centroid technique, and the solution from Global CMT Catalog, United States, determined with moment tensor technique are given in Table 2 and Fig. 6.7. According to all the solutions shown in Table 2 the earthquake occurred under prevailing compressive stress oriented to the south or south-southeast. One of nodal planes – NP1 – has a low-angle dipping (DP = 36º, 19º, 36º), the other one – NP2 – is steep (DP = 60º, 71º, 60º). The strike of NP1 plane is south-west (IPC GS RAS), sub-latitudinal (NEIC) or west-south-west (Quick CMT), NP2 – north-east (IPC GS RAS) or sub-latitudinal (NEIC, Quick CMT). According to the NEIC solution, slip direction in space for NP1 plane is thrust of northern flank, and for NP2 plane – reverse fault of southern flank of the fault. According to the solutions of other centers presented in Table 2, type of motion for NP1 plane is thrust with left-lateral strike-slip components, at which uplift of north-west (IPC GS RAS) or northern (Quick CMT) flank has occurred, and for NP2 plane – reverse fault of south-east or southern flank respectively. Seismic moment obtained in IPC GS RAS from P-wave spectrum of “Talaya” station (Δ= 43.36º) is Mo = 9.6 * 19 N*m. Average value of moment magnitude Mw calculated under Kanamori formula makes Mw = 7.3. According to NEIC USGS solution, seismic moment is Mo = 9.9 * 10 ** 19 N*m and moment magnitude Mw = 7.3, and Mo = 6.4 * 10 ** 19 N*m, Mw = 7.3 by Global CMT solution.
|
| 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 |
| 68 | 22 | 12 | 145 |
18 | 239 | 213 | 36 | 59 | 70 |
60 | 111 | IPC GS RAS | | 63 | 344 | 26 | 173 |
4 | 81 | 272 | 19 | 101 | 80 |
71 | 86 | NEIC | | 68 | 56 | 12 | 179 |
17 | 273 | 248 | 36 | 60 | 104 |
60 | 110 | 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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