Information message about the strong earthquake near the Java Island, Indonesia, September 2, 2009. |
| Destructive earthquake with M=7 and victims has occurred on September 2 at 07:55 GMT (11:55 Moscow time) near the coastline of central part of Java Island. |
| 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 21 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 59 stations, accurate processing - with data 63 stations. |
| Fig. 1 presents fragments of records obtained from digital stations Tennant Creek (∆ 28.6º), Diego Garscia (∆ 34.8º), Port Moresby (∆ 39.2º), Taejon (∆ 47.7º), Vladivostok (∆ 55.3º). Fig. 2 presents fragments of records obtained from digital stations Hailar (∆ 57.8º), Ala Archa (∆ 58.5º), Talaya (∆ 59.3º), Borovoe (∆ 68.3º), Yakutsk (∆ 71.7º).
|
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 |
07-55-00.0 |
-7.76 |
107.55 |
60 |
63 |
7/27 | 7.1/36 | 7-7.5 | 136 | IPC GS RAS (Accurate) | | 2 |
07-55-00.0 |
-7.76 |
107.53 |
60 |
59 |
7/27 | 7.1/33 | 7-7.5 | 150 | IPC GS RAS (Preliminary) | | 3 |
07-55-04.3 |
-7.78 |
107.41 |
70 |
614 |
7.1Mw | | | 47 | CSEM | | 4 |
07-55-02.0 |
-7.84 |
107.26 |
63 |
49 |
7.4Mw | 6.8/46 | | | NEIC (Preliminary) | | 5 |
07-55-01.7 |
-7.77 |
107.32 |
50 |
209 |
7.0Mw | 6.8/115 | | 29 | NEIC (Accurate) | |
| 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 red star epicenter of this earthquake, which was located near Java Island, Indonesia, at the depth of 60 km, 95 km South off Bandung, 196 km S-S-E off Jakarta (Capital of Indonesia). |
Figure 3 |
|
| Aftershock |
| GS RAS registered 1 aftershock with М=5.1, which has occurred in 1.5 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 |
| 20092842 | 2009-09-02 09:28:39.0 | -7.96 | 107.44 | 33 | 10 | - | 5.1/ 9 | 3.5-4 | Java, Indonesia | |
| Macroseismic manifestations |
| The number of victims of this earthquake, which occurred near the coast of Indonesian Island Java reached 57 persons. Official information agency Antara reported about 30 persons killed by the landslide in one village. Information was obtained about more than 700 buildings and living houses damaged by this earthquake. Vibration of buildings was observed in the capital and people were evacuated from them. Many houses were damaged in the living places located closer to the epicenter of this earthquake. |
Figure 4 | 
Figure 5 |
|
| Historical records |
| Indonesia is located in one of the most seismically active zones of the Earth, which is part of the so called Pacific fire ring. This region of the globe contains Australian and Sunda active tectonic planes. Annually 6-7 thousand earthquakes with M more than 4,0 are registered in this region.
The last destructive earthquake has occurred on July 17, 2006 near the western coast of Java Island , it caused tsunami with wave height of 5 meters. At that time more than 300 people were killed.
|
| Focal mechanism and seismic moment of the earthquake |
| Focal mechanism solutions of the earthquake which occurred on September 2, 2009 at 07:55 were obtained with CMT technique in NEIC USA and in USGS Center - Global CMT Catalog, USA, they are presented in table 2 and shown on fig. 6,7. The obtained solutions are similar.
This earthquake has occurred under the action of S-E oriented compression forces oriented. Both nodal planes had N-E direction of propagation and were rather steeply falling (falling angles of these planes vary within the range DP=45º-51º). Type of motion along both nodal planes– uplift (with right side drift components along NP1 and left side drift components along NP2).
The value of seismic moment Мо of the earthquake September 2, 2009 was calculated in IPC GS RAS from spectra of Р-waves obtained from three stations: Talaya (Δ 59.3º), Kislovodsk (Δ 77.8º), Obninsk (Δ 85.6º), it makes 1.7* 10** 20 n*m, the value of moment magnitude was calculated from Kanamori formula and it makes Mw = 7.4.
The value of seismic moment Мо in accordance with USGS makes 3.9* 10** 19 n*m, the value of moment magnitude Mw=7.0; and in accordance with Global CMT Catalog – Mo= 3.59* 10** 19 n*m and Mw=7.0. |
| 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 |
| 71 | 33 | 2 | 128 |
18 | 219 | 56 | 50 | 115 | 201 |
46 | 63 | NEIC | | 71 | 40 | 3 | 302 |
19 | 211 | 51 | 45 | 117 | 195 |
51 | 65 | Quick CMT | |
| NEIC - National Earthquakes Information Center of US Geological Service |
| Quick CMT - Quick CMT catalog |
Figure 6 | 
Figure 7 |
|
