Information message about the strong earthquake near the Bonin Islands, Japan, May 30, 2015 |
| The strong earthquake M=7.8 has occurred on May 30, 2015 at 11:23 GMT (14:23 Moscow time) near the Bonin Islands, Japan region. |
| 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 8 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 18 stations, accurate processing - with data 39 stations. |
| Fig. 1 presents fragments of records obtained from digital stations Matsushiro (∆ 9º), Taejon (∆ 14.1º), Erimo (∆ 14.4º), Mys Shultsa (∆ 16.6º), Yuzhno-Kurilsk (∆ 16.8º). Fig. 2 presents fragments of records obtained from digital stations Seimchan (∆ 36º), Bilibino (∆ 43.2º), Borovoe (∆ 56.6º), Arti (∆ 63º), Obninsk (∆ 75.1º). |
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 |
11-23-00.7 |
27.78 |
140.54 |
680 |
39 |
| 7.8/20 | | 139 | IPC GS RAS (Accurate) | | 2 |
11-22-54.8 |
27.2 |
140.7 |
600 |
18 |
| 7.8/14 | | 139 | IPC GS RAS (Preliminary) | | 3 |
11-23-03.2 |
27.91 |
140.46 |
693.2 |
290 |
Mw 7.8 | | | 24 | CSEM | | 4 |
11-23-02.8 |
27.83 |
140.49 |
677.6 |
111 |
Mw 7.8 | | | 28 | NEIC | | 5 |
11-23-00.0 |
27.9 |
140.8 |
590 |
|
MJMA 8.5 | | | | JMA | |
| 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 |
| JMA - Japan Meteorological Agency |
| Epicenter |
| Fig.3 presents with red epicenter of this earthqquake, its origin was located in the Pacific Ocean, in the area of Bonin Islands of Japan, at the depth of 680 km, 853 km S of Yokohama, 883 km S of Tokyo - the Capital City of Japan and 898 km S-E of Osaka.
|
Figure 3 |
|
| Aftershock |
| GS RAS registered aftershock with M=4.9 within one day 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 |
| 20151978 | 2015-05-31 08:46:18.0 | 28.3 | 139.64 | 450 | 45 | - | 4.9/ 19 | - | Bonin Islands, Japan region | |
| Macroseismic manifestations |
| According to ITAR-TASS as a result of this earthquake 12 persons suffered. All of them are residents of Tokyo and nearby prefectures Saitama and Kanagawa. There is no information about victims. The earthquake also led to transport problems. In particular, it terminated the movement of high-speed trains "Shinkansen" between Tokyo and Osaka. The earthquake did not affect restoration works at the NPP "Fukushima-1", however, it led to the temporary shutdown of electricity in 600 homes in neighboring Tokyo, Saitama Prefecture.
Fig. 4, was obtained from USGS NEIC WEB site, it presents USGS Community Internet Intensity Map based on 346 responses in 131 cities of Japan, China, Taiwan, South Korea remote to 2500 km of the epicenter. |
Figure 4 |
|
| Historical records |
| The epicenter was located 155 km north of the epicenter of the strong earthquake October 7, 1968 with magnitude M=7.3 and depth of the origin of 500 km. |
| Focal mechanism and seismic moment of the earthquake |
| Focal mechanism solution of the origin was obtained in IPC GS RAS with signs of initial arrivals of P waves at 99 stations including 39 of them which registered the waves of compression (plus signs) and 60 stations which registered tensile waves (minus signs). These stations are located in the interval of epicentral distances 1–97º and in azimuth sector Az=1-355º. Focal mechanism solution in stereographic projection at the lower hemisphere is presented at fig. 5, elements of mechanism are presented in table 2. Fig. 6, 7 present focal mechanism solutions obtained in USGS NEIC with W-phase Moment Tensor (Mww) technique and in Quick CMT Center with CMT technique. Elements of these solutions are also presented in table 2. Solutions obtained in different centers are similar. |
| 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 |
| 22 | 272 | 53 | 34 |
28 | 169 | 159 | 72 | -120 | 42 |
34 | -32 | IPC GS RAS | | 29 | 269 | 54 | 49 |
19 | 169 | 163 | 76 | -110 | 41 |
24 | -35 | NEIC | | 26 | 268 | 56 | 45 |
20 | 168 | 162 | 74 | -111 | 37 |
26 | -38 | 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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