Information message about the strong earthquake in Aegean Sea, May 24, 2014. |
| The strong earthquake M=6.9 has occurred on May 24, 2014 at 09:25 GMT (13:25 Moscow time) in Aegean Sea. |
| 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 27 stations, accurate processing - with data 44 stations. |
| Fig. 1 presents fragments of records obtained from digital stations Apeiranthos of Naxos (∆ 3.3º), Kasperske Hory (∆ 12.2º), Kislovodsk (∆ 13.3º), Obninsk (∆ 16.5º), Pulkovo (∆ 19.7º). Fig. 2 presents fragments of records obtained from digital stations Borovoe (∆ 32.7º), Kurchatov (∆ 37.9º), Talaya (∆ 53º), Tiksi (∆ 56.3º), Yakutsk (∆ 61.3º).
|
Figure 1
| 
Figure 2
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|
| 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 |
09-25-01.3 |
40.35 |
25.44 |
10 |
44 |
6.9/25 | 6.4/21 | 9.5-10 | 133 | IPC GS RAS (Accurate) | | 2 |
09-25-02.7 |
40.36 |
25.34 |
10 |
27 |
| 6.2/17 | 8-8.5 | 140 | IPC GS RAS (Preliminary) | | 3 |
09-25-02.9 |
40.29 |
25.4 |
27 |
33 |
6.9 Mw | | | 108 | CSEM | | 4 |
09-25-03.4 |
40.305 |
25.453 |
10 |
580 |
6.8/99 | | | 25 | NEIC | | 5 |
09-25-02.9 |
40.26 |
25.39 |
10 |
203 |
6.5 Mw | | | | GFZ | |
| 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 |
| GFZ - German Research Center for Geosciences |
| Epicenter |
| Fig. 3 presents with red star epicenter of this earthquake which origin was located in Aegean Sea close to Samothrace Island, Greece, at the depth of 10 km, 12 km S of Kamariotissa, Greece, 86 km W-N-W of Çanakkale, Turkey, and 93 km S-S-W of Alexandroupoli, Greece. |
Figure 3 |
|
| Aftershock |
| GS RAS registered 5 aftershocks with M>=4.4 within 15 hours after the main shock. |
| 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 |
| 20141921 | 2014-05-24 11:33:06.0 | 40.3 | 25.66 | 10 | 16 | - | 4.6/ 7 | 4.5 | Aegean Sea | | 20141923 | 2014-05-24 12:46:00.0 | 40.21 | 25.13 | 10 | 12 | - | 4.4/ 4 | 4 | Aegean Sea | | 20141924 | 2014-05-24 14:49:15.0 | 40.63 | 25.6 | 10 | 18 | - | 4.6/ 12 | 4.5 | Aegean Sea | | 20141925 | 2014-05-24 16:50:00.0 | 39.98 | 24.34 | 10 | 12 | - | 4.4/ 6 | 4 | Aegean Sea | | 20141928 | 2014-05-25 00:07:58.0 | 40.08 | 24.16 | 10 | 21 | - | 4.7/ 10 | 4.5-5 | Aegean Sea | |
| Macroseismic manifestations |
| According to RIA-Novosti about 270 persons suffered in Turkey after this earthquake. Hundreds of people leaved their homes frightened by potential crash of the buildings. This panics resulted in numerous injuries. Many persons were carried to hospitals with heart attacks. Cracks have formed in the walls of some houses, the minor destructions were observed in prayer towers of mosques.
At Lemnos and Samothrace islands of Greece a few old buildings were destroyed. Little damage was caused by the airport on Lemnos, archaeological Museum in Mirinas suffered.
Fig. 4, presents USGS Community Internet Intensity Map, based on 447 responses in 125 cities. |
Figure 4 |
|
| Focal mechanism and seismic moment of the earthquake |
| Focal mechanism was obtained in IPC GS RAS by signs of initial arrivals of P waves at 89 stations, including 39 stations which registered the waves of compression (plus signs) and 50 stations which registered transverse waves (minus signs). These stations are located in the interval of epicentral distances of 2–97º and are dispersed rather uniformly along th azimuths. Focal mechanism solution of the origin in stereographic projection at the lower hemisphere is presented at fig. 5, elements of mechnism are presented in table 2.
Fig. 6, 7 present focal mechanism solutions obtained in USGS NEIC with tensor moment technique and long period spatial waves (Mww) and in Quick CMT Catalog, USA with CMT technique.
Both solutions are close. The earthquake has occurred under the action of nearly equal in value compression and tension stresses. Compression stresses were S-E-N-W oriented. Transverse streses were S-W–N-E oriented. Both nodal planes are steeply dipping (DP=77-90º). Nodal plane NP1 in solutions of both centers strikes S-W–N-E (STK=79-251º), plane NP2 strikes S-E–N-W (STK=163-341º). In accordance with IPC GS RAS the motion in origin is characterized as pure slip. According to USGS and Quick CMT the motion along both planes is characterized as strike-slip with minor reverse components, for NP1 this is right lateral strike-slip and for NP2 – left lateral strike-slip.
Seismic moment was obtained in IPC GS RAS with Р waves spectra registered at «Talaya» station (∆53.01º), Mo=1.6*10**19 N*m, Mw=6.8. According to USGS NEIC – Mo=2.56*10**19 N*m, Mw=6.9, according to Quick CMT Mo=2.53*10**19 N*m, Mw=6.9. |
| 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 |
| 0 | 206 | 0 | 116 |
90 | 344 | 251 | 90 | -180 | 341 |
90 | 0 | IPC GS RAS | | 17 | 29 | 1 | 298 |
73 | 206 | 72 | 77 | 168 | 165 |
79 | 13 | NEIC | | 3 | 28 | 4 | 118 |
85 | 259 | 253 | 90 | -175 | 163 |
85 | 0 | 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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