Information message about the earthquake in the north-eastern part of Sakha Republic on June 22, 2008

     The earthquake with M=6 has happened on June 22, 2008 at 23:56 GMT (June 23 at 3:56 Moscow time) in the north-eastern part of Sakha Republic.
     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 25 min after registration to the Ministry of Emergency of the Russian Federation (EMERCOM).
     Preliminary processing has been done with data from 33 stations, accurate processing - with data 55 stations.
     Fig. 1 presents fragments of records obtained from digital stations Tiksi (∆ 5.9º), Seimchan (∆ 6.6º), Yakutsk (∆ 7.5º), Bilibino (∆ 9.5º), Petropavlovsk (∆ 16.9º), Yuzhno-Sakhalinsk (∆ 20.8º). Fig. 2 presents fragments of records obtained from digital stations Kurchatov (∆ 34.5º), Borovoe (∆ 35.7º), Arti (∆ 37.3º), Obninsk (∆ 45.5º), Kislovodsk (∆ 53.3º), Garni (∆ 56º).

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 23-56-28.6 67.69 141.36  20  55  6/166.2/267-7.5 51 IPC GS RAS (Accurate)
2 23-56-30.7 67.71 141.43  33  33  5.9/146.3/176.560 IPC GS RAS (Preliminary)
3 23-56-29.6 67.74 141.32  30  181  5.9Mw   48 CSEM
4 23-56-29.9 67.67 141.41  12.6  46  5.9Mw 6.0/40 79 NEIC (Accurate)
5 23-56-29.1 67.78 141.13  10  218  5.9Mw 6.2/197  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 round epicenter of this earthquake, which was located in the north-eastern part of Sakha Republic, at 222 km to the west-south-west from Belaya Gora, at 339 km to the east from Verkhoyansk, at 359 km to the north-north-west from Ust-Nera, at 653 km to the south-east from Tiksi, at 834 km to the north-east from Yakutsk.

    Figure 3
    Aftershock
         GS RAS registered 2 aftershocks with magnitude M=4.9 and M=4 within 3 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
    200821722008-06-23 01:02:45.067.82141.293312-4.9/ 53-3.5 Eastern Siberia, Russia
    200821732008-06-23 02:31:55.067.59141.35337-4.0/ 2-Eastern Siberia, Russia
    Historical records
         This earthquake on June 22, 2008 has occurred in the origin zone of sensitive Selenyakhsk earthquake dated on January 7, 1999 at 18h13m (GMT) with КР=13.0, M=5.0, which happened between two rivers Indigirka and it’s left branch Selennyakh (Andrei-Tas Ridge), near the north -eastern part of Momo-Selennyakhsk Neozoic depression (fig. 4). Though the main shock of the earthquake of 1999 has occurred in unpopulated area, it was noticed by local hunters, who were sleeping in tent at 60 km to the southо-east from epicenter. Approximatly at 5 o’clock local time in the morning they’ve heard the strong roar, like the explosion and felt the sharp shock of the ground. The candle has fallen down from the table. After that in the morning they observed the place around and found rather broad (up to 40 m) and long (up to 100 m) stripe of snow, which has fallen from the trees [B.M. Kozmin, 2005].
    Focal mechanism and seismic moment of the earthquake
         For Selennyakhsk earthquake 1999 focal mechanism solution of the motion in origin in accordance with NEIC USA corresponds to: thrust along the flat laying plane and uplift – along the steeply falling plane. Focal mechanism solution of the earthquake 2008 in accordance with NEIC (see. Table 2) is very close to the solution of the earthquake 1999: the motion in origin along both nodal planes corresponds to uplift (along NP1 – with left slip component, along NP2 – with right slip component). Propagation of planes in case of the earthquake 2008 corresponds to orientation of Chersky Ridge. For the earthquake 22.06.2008 the value of seismic moment Мо obtained by IPC GS RAS from Р-wave spectra at three stations: "Arti" – delta 37.3 degrees, "Obninsk" – delta 45.5 degrees, "Kislovodsk" – delta 53.3 degrees makes Мо=2.4* 10** 18 n*m. The value of moment magnitude calculated from Kanamori formula Mw = 6.2; The value of seismic moment Мо for the earthquake 22.06.2008 in accordance with NEIC makes 1.0* 10** 18 n*m, the value of moment magnitude makes Мw=5.9. Fig. 4 shows epicenters of the earthquakes January 7, 1999 at 18h13m with MS=5.0, КР=13.0 and of the earthquake June 22, 2008 with MS=6.0 (red arrow) near Momo-Selennykhsky depression: 1 – main shock on January 7, 1999 at 18h13m; 2–4 it’s aftershocks with КР=10.9, 10.1, 9.5 respectively; 5 – ruptures (slips and thrusts in accordance with [Rupture tectonics of Yakut Republic territory, 1976]); 6 – Neozoic deposits of Momo-Selennykhsky depression; 7 – focal mechanisms in accordance with NEIC.
    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
    6529723134 6411084455332 55119NEIC
  • NEIC - National Earthquakes Information Center of US Geological Service

    • Figure 4


    News | Catalogs | Wave Forms | Alert Service | Software | Links | Srtucture | Publications | Conferences | Announce | About
    © FRC GS RAS 1993-2018