Information message about destructive earthquake in the Northern Qinghai, China, April 13, 2010. |
| The earthquake with magnitude 6.9 has occurred on April 13, 2010 at 23:49 GMT (April 14, 2010 at 3:49 Moscow time) in the North Qinghai, China. It caused victims and destructions. |
| 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 15 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 57 stations, accurate processing - with data 69 stations. |
| Fig. 1 presents fragments of records obtained from digital stations Ulaanbaatar (∆ 16.6º), Talaya (∆ 19.1º), Ala Archa (∆ 19.8º), Kurchatov (∆ 21.9º), Hailar (∆ 23.5º). Fig. 2 presents fragments of records obtained from digital stations Arti (∆ 34.9º), Kislovodsk (∆ 42.8º), Storozhevoe (∆ 45º), Obninsk (∆ 46.6º), Petropavlovsk (∆ 47.7º). |
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 |
23-49-36.3 |
33.24 |
96.68 |
10 |
69 |
6.9/34 | 6.6/34 | 9.5-10 | 48 | IPC GS RAS (Accurate) | | 2 |
23-49-38.5 |
33.11 |
96.67 |
33 |
57 |
6.9/33 | 6.6/31 | 8 | 70 | IPC GS RAS (Preliminary) | | 3 |
23-49-40.8 |
33.27 |
96.676 |
33 |
148 |
6.8Mw | | | 48 | CSEM | | 4 |
23-49-37.9 |
33.271 |
96.629 |
10 |
|
6.9Mw | 6.3/45 | | 50 | NEIC (Accurate) | | 5 |
23-49-42.1 |
33.263 |
96.665 |
47 |
60 |
6.9Mw | 6.4/26 | | | 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 |
| The red star on fig.3 presents epicenter of the earthquake, which origin was located in mountainous area of Qinghai province, China, at the depth of 10 km, 240 km N-N-W Qamdo, 655 km N-E of Lhasa and 1900 km W-S-W from Beijing. |
Figure 3 |
|
| Aftershock |
| The foreshock with magnitude 5 has occurred 2 hours before the main shock.
GS RAS registered also 4 aftershocks with М>=5 within four 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 |
| 20101394 | 2010-04-13 21:39:59.0 | 33.05 | 96.67 | 33 | 16 | - | 5.0/ 11 | 3.5-4 | Qinghai, China | | 20101399 | 2010-04-14 00:01:18.0 | 32.83 | 96.92 | 33 | 23 | - | 5.4/ 12 | 4.5 | Qinghai, China | | 20101400 | 2010-04-14 00:12:22.0 | 33.13 | 96.74 | 10 | 36 | - | 5.3/ 11 | 6-6.5 | Qinghai, China | | 20101401 | 2010-04-14 01:25:14.0 | 33.2 | 96.54 | 10 | 54 | 6.1/ 21 | 6.0/ 34 | 8.5-9 | Qinghai, China | | 20101404 | 2010-04-14 03:15:48.0 | 32.91 | 96.43 | 33 | 28 | - | 5.0/ 15 | 3.5-4 | Qinghai, China | |
| Macroseismic manifestations |
| In accordance with RIA-Novosti the number of killed people reached 617, destiny of 313 local residents is still unknown. The number of injured at present time is equal to 9,11 thousands, 970 of them are heavily injured. Rescue operation is under way now, it is reported about destroyed houses and schools, most of these buildings are one storey houses of clay and wood. In accordance with local media up to 90% of buildings were destroyed in the district, cell phone and power supply systems are damaged (fig. 4). |
Figure 4 |
|
| Historical records |
| Epicenter of this earthquake was 660 km W-N-W from epicenter of another destructive earthquake of May 12, 2008, which occurred in Eastern Sichuan with М=8. At that time more than 87 thousand people were killed. |
| Focal mechanism and seismic moment of the earthquake |
| Focal mechanism of the origin for the earthquake of April 13, 2010 (23:49 GMT) was calculated in IPC GS RAS with first signs of Р-wave arrivals at 140 stations, with 64 of these stations registered the waves of compression (plus sign), while 76 stations registered the waves of expansion (minus sign). These stations are located in the interval of epicentral distances of Δ=6-135º with rather even distribution along azimuth. Focal mechanism of the origin in stereographic projection of lower hemisphere is presented in figure 5, elements of this mechanism are presented in table 2. Table 2 and figures 6, 7 present focal solution obtained with CMT technique in USGS and in Global CMT Catalog, USA.
Both solutions are similar. The earthquake has occurred under the action of almost equal expansion and compression forces oriented to N-S and N-E respectively. One nodal plane (NP1) propagates to N-W direction, the other (NP2) – to N-E direction. For the plane with N-W direction of propagation the values of STK are nearly the same (STK=300-303º), while the values of DP vary within the range of 31 degrees (DP=59-90º). The type of motion along this plane – left side slip (in case of Р-waves – with uplift component, in accordance with USGS – with uplift component, in accordance with Global CMT – with vertical component).
For the plane NP with N-E direction of propagation all solutions give the similar values of STK and DP, they differ only within the range of 20 degrees – (STK=209-225º), (DP=58-77º). The type of motion along this plane – right side slip (in case of Р-waves with uplift component, in accordance with USGS with uplift component, in accordance with Global CMT – «pure» slip.
The value of Мо for this earthquake of April 13, 2010 was obtained by IPC GS RAS with Р-wave spectra from three stations: «Arti» (Δ 20.53º), «Kislovodsk» (Δ 42.90º), "Obninsk" (Δ 46.73º), it makes Мо=7.1* 10** 18 n*m. The value of Mw was calculated with Kanamori formula and makes Mw=6.5.
The value of Мо in accordance with USGS makes 2.5* 10** 19 n*m and Mw=6.9, in accordance with Global CMT Catalog – Мо= 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 |
| 8 | 352 | 36 | 88 |
53 | 252 | 123 | 59 | -22 | 225 |
71 | -147 | IPC GS RAS | | 25 | 169 | 19 | 70 |
57 | 307 | 301 | 58 | 175 | 301 |
86 | 32 | NEIC | | 9 | 166 | 9 | 74 |
77 | 300 | 120 | 90 | -13 | 210 |
77 | -180 | 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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