Information message about the earthquake in Eastern Turkey on May 1, 2003. |
| On May 1, 2003 the destructive earthquake has happened in Eastern Turkey. It occurred at 04:27 Moscow time (00:27 GMT) and had magnitude 6.3.
|
| 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 1 ÷ 48 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 30 stations, accurate processing - with data 45 stations. |
| Figure 1 presents vertical component (BHZ) recordings at digital station Garni (with delta 3.4 degrees) and three component (BHZ, BHN, BHE) recordings at digital station Kislovodsk (with delta 5.2 degrees). Figure 2 represents fragments of records for vertical component (BHZ) registered on digital stations: Arti (delta 21 degrees), Borovoe (delta 25 degrees), Lovozero (delta 29 degrees), Talaya (delta 45 degrees), Bilibino (delta 66 degrees).
|
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 |
00-27-04.20 |
39 |
40 |
10 |
45 |
6.30/17 | 5.60/13 | 8.5 | 90 | IPC GS RAS (accurate) | | 2 |
00-27-07.60 |
39 |
40 |
33 |
30 |
6.3/10 | 5.60/8 | 7-7.5 | 217 | IPC GS RAS (preliminary) | | 3 |
00-27-04.70 |
38 |
40 |
10 |
251 |
| 4.5-5.9 | | 33 | CSEM | | 4 |
00-27-08.72 |
38 |
40 |
33 |
88 |
| 5.7 | | | NEIC (preliminary) | | 5 |
00-27-04.86 |
38 |
40 |
10 |
144 |
6.4/67 | 5.7/74 | | | NEIC (accurate) | | 6 |
00-27-04.00 |
39 |
40 |
5 |
|
6.4 | | | | KRIPC | |
| 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 |
| KRIPC - Regional Informational Processing Center of Kamchatka |
| Aftershock |
| In the period between May 1 and 4, 2003 more than 200 aftershocks with magnitudes 2.8 - 4.5 MSK have been registered in origin place (data of agency BU KOERI, Department of Geophysics, Istanbul, TURKIY
http://www.koeri.boun.edu.tr/scripts/lasteq.asp).
|
| Macroseismic manifestations |
| The earthquake on May 1, 2003 has happened in the East of Turkey, in Bengol province, 665 km to the East from capital Ankara. It was felt on significant part of Eastern Turkey territory. According to ITAR TASS data on May 5, 2003 167 people died and 521 were injured with big number of buildings destroyed.
|
| Historical records |
| Turkeys territory is the tectonically active region, in the zone of interaction between two plates: Arabic and Eurasian. Destructive earthquakes happen often here. Significant part of continental crust is presented by Anatolian block, which sustains compression in the Western direction. The block is bounded to the north by the North Anatolian Fault and to the south-east by the East Anatolian fault. Epicenter of the earthquake on May 1, 2003 occurred near the east end of the East Anatolian fault. This earthquake may be the result of rupture on the North-Eastern trending East-Anatolian Fault or it may have occurred on the northwest trending Bingol Karakocan fault zone.
    The earthquake on May 1, 2003 has continued series of numerous destructive earthquakes, which Turkey has suffered in the nearest past. This earthquake occurred 70 km to the South-East from the earthquake on January 27, 2003 with magnitude М=6.1, which resulted in one killed person and a few injured. Izmit earthquake of 1999 (М=7.6), which happened 1500 km to the West from the earthquake on May 1, 2003 has killed 17000 people and left 500000 people homeless.
    At the time of two destructive earthquakes in Erzindjan (nearly 120 km to the North-West from current epicenter), on March 13, 1992 (М=6.6) hundredes of people have been killed and thousands have been left homeless, after more destructive earthquake in 1939 (М=8.0) 33000 people have been killed (see http://wwwneic.cr.usgs.gov/neis/bulletin/neic_tgac.html).
|
Figure 3 |
|
| Focal mechanism and seismic moment of the earthquake |
| Focal mechanism solution of the earthquake 01.05.2003 has been calculated with CMT method in NEIC - National Earthquakes Information Center of the US Geological Service http://wwwneic.cr.usgs.gov/neis/FM/neic_tgac_q.html and in Harvard Center HARVARD (USA) http://www.seismology.harvard.edu (HRV), these solutions are given in table 2 and are shown on figures 3-4 in stereographical projection (lower hemisphere).
As it is seen, focal mechanism solutions obtained from data of different centers have common features. Motion in source was caused by action of compression and dilatations strengths oriented near longtitude and latitude respectively. Nodal planes (NP1) in all solutions have North-Eastern spread direction (Stk=64, Stk=236 degr. ) and steep fall (dp=88, dp=75 degr.), nodal planes (NP2) have North-Western spread direction (Stk=334, Stk=332 degr. ) and steep fall (dp=90, dp=69 degr.), motion in source is characterized as strike-slip. Spread directions of NP1 and NP2 correspond with orientation of tectonics ruptures, which intersect North-Anatolian block.
Seismic moment Мо determined in IPC GS RAS from Р-wave spectra at "Talaya" station (delta=44.8 degr.) made the value Mo=1.7*10*18 n*m. The value of moment magnitude from these data - Mw=6.1. The value of seismic moment Mo determined in NEIC made Mo=4.4*10*18 n*m, the value of moment magnitude Mw=6.4. The value of seismic moment Mo obtained in HRV made Mo=4.1*10*18 n*m, the value of moment magnitude Mw=6.3. As it is seen, the values of Mo and Mw obtained from different centers are close to each other respectively.
|
| 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 |
| 1 | 289 | 1 | 19 |
88 | 154 | 64 | 88 | 0 | 334 |
90 | 178 | NEIC | | 4 | 285 | 26 | 193 |
64 | 23 | 236 | 75 | -22 | 332 |
69 | -164 | HARVARD | |
| NEIC - National Earthquakes Information Center of US Geological Service |
| HARVARD - Harvard Geophysical Center (USA) |
Figure 4 | 
Figure 5 |
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