Information message about sensitive earthquake in Okhotsk Sea on July 5, 2008 |
| The deep and sensitive earthquake has occured on July 5, 2008 at 2:12 am. GMT (6:12 am. Moscow time) in Okhotsk Sea with М=7.2. |
| 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 30 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 56 stations, accurate processing - with data 75 stations. |
| Gig. 1 presents fragments of records obtained from digital stations Petropavlovsk (∆ 3.5º), Seimchan (∆ 9.1º), Yuzhno-Sakhalinsk (∆ 9.5º), Yuzhno-Kurilsk (∆ 10.9º), Erimo (∆ 13.6º). Fig. 2 presents fragments of records obtained from digital stations Yakutsk (∆ 14.7º), Bilibino (∆ 15.6º), Vladivostok (∆ 17.6º), Matsushiro (∆ 20.1º), Tiksi (∆ 20.7º). |
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 |
02-12-02.9 |
53.87 |
152.99 |
630 |
75 |
| 7.2/36 | 4-5 | 38 | IPC GS RAS (Accurate) | | 2 |
02-12-01.4 |
53.95 |
152.98 |
600 |
56 |
| 7.2/23 | 4-5 | 38 | IPC GS RAS (Preliminary) | | 3 |
02-12-02.7 |
53.91 |
152.98 |
630 |
286 |
7.5Mw | | | 38 | CSEM | | 4 |
02-12-04.6 |
53.89 |
152.88 |
633 |
326 |
7.7Mw | 6.8/238 | | 22 | NEIC (Accurate) | | 5 |
02-12-03.5 |
53.89 |
153.03 |
605 |
|
7.5Mw | 7.3/9 | | | NEIC (Preliminary) | |
| 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 |
| Epicenter |
| Fig.3 depicts with blue circle epicenter of this earthquake, which was located in Okhotsk Sea at 190 km to the western coast of Kamchatka at the depth of 630 km and 395 km WNW of Petropavlovsk-Kamchatsky, 420 km NNW of Severo-Kurilsk, 650 km SSE of Magadan. |
Figure 3 |
|
| Aftershock |
| In 18 minutes after the main shock GS RAS has registered aftershock with magnitude М=5.5 |
| 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 |
| 20082307 | 2008-07-05 02:30:53.0 | 53.93 | 154.22 | 490 | 36 | - | 5.5/ 16 | - | Sea of Okhotsk | |
| Macroseismic manifestations |
| This earthquake has been felt in Petropavlovsk-Kamchatsky with intensity 3-4 MSK, in Severo-Kurilsk with intensity 3 MSK, in Holmsk, Yuzhno-Sakhalinsk, Komsomolsk-na-Amure, Okha, Khabarovsk with intensity 2-3 MSK. |
| Focal mechanism and seismic moment of the earthquake |
| Focal mechanism solutions of this earthquake 05.07.2008 have been calculated with TMC method in NEIC, USGS and Harvard Center USA, HRVD (Global CMT Catalog) and are presented in table 2 and shown on Fig. 4, 5. THe obtained mechanismsm are very similar.
THe earthquake has happened under prevailing action of expansion forces oriented to the east. Both nodal planes lay rather steep. Nodal plane NP1 propagates from the north-west to the south-east, nodal plane NP2 - from the north-east to the south-west. The type of motion along both planes – fault with drift components (right side for NP1 and left side for NP2).
The value odf seismic moment Мо of the earthquake 05.07.2008 in accordance with USGS makes 3.9* 10** 20 n*m, the value of moment magnitude Mw = 7.7; in accordance with HRVD Мо=4.16* 10** 20 n*m, Mw = 7.7.
|
| 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 |
| 8 | 88 | 57 | 344 |
30 | 183 | 147 | 45 | -135 | 23 |
61 | -53 | NEIC | | 8 | 87 | 59 | 344 |
30 | 182 | 147 | 45 | -134 | 21 |
59 | -55 | HARVARD | |
| NEIC - National Earthquakes Information Center of US Geological Service |
| HARVARD - Harvard Geophysical Center (USA) |
Figure 4 | 
Figure 5 |
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