Information message about the strong earthquake near east coast of Honshu, Japan, November 21, 2016 |
| The strong earthquake M=7.1 occurred on November 21, 2016 at 20:59 GMT (23:59 Moscow time) near east coast of Honshu, Japan. |
| 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 9 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 23 stations, accurate processing - with data 65 stations. |
| Fig. 1 presents fragments of records obtained from digital stations Matsushiro (∆ 2.8º), Erimo (∆ 4.8º), Yuzhno-Kurilsk (∆ 7.4º), Kurilsk (∆ 9.1º), Yuzhno-Sakhalinsk (∆ 9.5º). Fig. 2 presents fragments of records obtained from digital stations Kuldur (∆ 13.8º), Petropavlovsk Group (∆ 19.3º), Magadan (∆ 23º), Yakutsk (∆ 25.7º), Bilibino (∆ 33.7º). |
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 |
20-59-45.9 |
37.42 |
141.54 |
10 |
65 |
7.1/24 | 6.6/27 | 10-10.5 | 109 | IPC GS RAS (Accurate) | | 2 |
20-59-57.1 |
37.72 |
141.7 |
33 |
23 |
| 6.3/7 | | 221 | IPC GS RAS (Preliminary) | | 3 |
20-59-49.4 |
37.38 |
141.4 |
10 |
674 |
Mw 6.9 | | | 32 | CSEM | | 4 |
20-59-49.0 |
37.39 |
141.4 |
11.3 |
125 |
Mw 6.9 | | | 59 | NEIC | |
| 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 presents with red star the epicenter of this earthquake, its origin was located near east coast of Honshu, Japan, at a depth of 10 km, 110 km S-E of Sendai, 247 km N-E of Tokyo, Japan's capital. |
Figure 3 |
|
| Aftershock |
| GS RAS registered 1 foreshock 2.5 hours before the main shock and 9 aftershocks М>=4.8 within 8 hours after it. |
| 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 |
| 20164108 | 2016-11-21 18:25:47.0 | 37.45 | 141.56 | 10 | 26 | - | 4.6/ 15 | 4.5 | Near east coast of Honshu, Japan | | 20164111 | 2016-11-21 21:10:21.0 | 37.56 | 141.29 | 10 | 22 | - | 5.5/ 11 | 6.5-7 | Near east coast of Honshu, Japan | | 20164112 | 2016-11-21 21:28:20.0 | 37.31 | 141.48 | 10 | 28 | - | 5.0/ 13 | 5-5.5 | Near east coast of Honshu, Japan | | 20164113 | 2016-11-21 21:39:40.0 | 37.36 | 141.25 | 10 | 46 | - | 5.5/ 19 | 6.5-7 | Near east coast of Honshu, Japan | | 20164114 | 2016-11-21 21:50:54.0 | 37.32 | 141.5 | 10 | 31 | - | 5.1/ 16 | 5.5-6 | Near east coast of Honshu, Japan | | 20164115 | 2016-11-21 23:39:49.0 | 37.13 | 141.56 | 10 | 25 | - | 5.0/ 16 | 5-5.5 | Near east coast of Honshu, Japan | | 20164118 | 2016-11-22 00:03:11.0 | 37.81 | 140.67 | 10 | 23 | - | 5.1/ 12 | 5.5-6 | Eastern Honshu, Japan | | 20164117 | 2016-11-22 01:31:23.0 | 37.14 | 141.57 | 10 | 28 | - | 5.1/ 15 | 5.5-6 | Near east coast of Honshu, Japan | | 20164119 | 2016-11-22 01:37:57.0 | 37.18 | 141.46 | 10 | 51 | - | 5.3/ 28 | 6-6.5 | Near east coast of Honshu, Japan | | 20164120 | 2016-11-22 04:26:07.0 | 37.11 | 141.41 | 10 | 19 | - | 4.8/ 14 | 4.5-5 | Near east coast of Honshu, Japan | |
| Macroseismic manifestations |
| According to RIA-Novosti, several thousand people have been evacuated to safe places. Operation of the airport in the city of Sendai was stopped. No major destruction of buildings have been reported. The maximum tsunami height reached 1.4 meters, and in the region of Fukushima NPP - one meter. Earthquake and tsunami did not damage operation of the nuclear power plants.
Fig. 4 was obtained from USGS NEIC, it presents USGS Community Internet Intensity Map based on 471 responses in 126 cities. |
Figure 4 |
|
| Historical records |
| The earthquake occurred in 283 km W of the strong earthquake October 25, 2013 M=7.3 and 140 km S-W of the devastating earthquake March 11, 2011 M=8.8. |
| Focal mechanism and seismic moment of the earthquake |
| The focal mechanism solution of the earthquake origin was calculated in IPC GS RAS with signs of initial arrivals of longitudinal waves at 92 stations, of which 9 stations registered the waves of compression (plus signs) and 83 stations - tensile waves (minus signs). These stations are located in the interval of epicentral distances 0.7-94º and azimuth sector Az = 5-353º. Focal mechanism in stereographic projection at lower hemisphere is shown in Fig. 5, the elements of the mechanism are shown in Table. 2. Fig. 6, 7 present focal mechanism solutions obtained in USGS NEIC with W-phase Moment Tensor (Mww) technique and in Lamont-Doherty Earth Observatory Global CMT Columbia University, USA (LDEO GCMT) with СМТ (Centroid moment tensor) technique. Solutions obtained in different centers are close.
The quake occurred under the influence of prevailing compression stresses SE oriented. Nodal plane lie almost vertically under the close angles (DP=41-65º), they strike NE (STK=45-61º) and SW (STK=222-232º). The type of motion – normal fault along both planes.
The seismic moment of the earthquake was obtained in IPC GS RAS from the spectra of longitudinal waves registered at the station "Obninsk" (∆ 67.85º), it makes Mo=4.4*10**19 N*m, Mw=7.1. According to USGS NEIC – Mo=3.25*10**19 N*m, Mw=6.9, according to LDEO GCMT – Mo=3.05*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 | 321 | 81 | 51 |
9 | 231 | 61 | 46 | -77 | 222 |
46 | -103 | IPC GS RAS | | 20 | 140 | 70 | 324 |
1 | 231 | 51 | 65 | -89 | 228 |
25 | -93 | NEIC | | 4 | 319 | 85 | 178 |
3 | 49 | 45 | 41 | -95 | 232 |
49 | -86 | GCMT | |
| IPC GS RAS - Informational Processing Center, Geophysical Survey, Russian Academy of Sciences |
| NEIC - National Earthquakes Information Center of US Geological Service |
| GCMT - Lamont-Doherty Earth Observatory Global CMT Columbia University, USA |
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