Information message about the earthquakes in the border area between Stavropol region and Ingush Republic within the period between December 22-25, 2001 |
| In the period between December 22 and December 25, 2001 the bunch of sensitive earthquakes has happened in the border area between Stavropol Region and Ingush Republic. Most significant of them have been felt on December 23 at 18:12 of Moscow time (15:12 GMT) with magnitude 3.2 and on December 25 at 09:03 of Moscow time (06:03 GMT) with magnitude 3.7, intensity of these events reached 4-5 MSK. |
| Parameters of these earthquakes have been determined in the Alert Service (AS) of Inofrmation Processing Center (IPC) of Geophysical Survey of RAS in Obninsk with station data obtained from digital and analog seismic stations of Russia and countries of CIS in a near to real time mode.
Data from 4 stations have been used in processing of the earthquake on December 23: Piatigorsk, Kislovodsk, Obninsk (Russia), Garni (Armenia), and from 6 stations in processing of the earthquake on December 26: Kislovodsk, Arti (Russia), Garni (Armenia), Borovoe (Kazakhstan), Ala-Archa (Kyrgyz). Alert messages on these earthquakes have been sent in 1 hour 30 minutes after their occurrence to the Ministry of Russian Federation dealing with civil defense, extraordinary situations and liquidation of natural disasters (MCHS). |
| Preliminary summary processing of the earthquake has been done with data from 4-6 stations. Fragments of three component records from Kislovodsk station (delta 170 km) and vertical component from Garni station (delta 430 km) are presented on figure 1. Both broadband (in blue color) and filtered in frequency band 0.7-3 Hz (in red color) records on vertical channels for more far located stations are given in figure 2: Arti (delta 1700 km), Borovoe (delta 2100 km) and Ala-Archa (delta 2400 km). |
Figure 1
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Figure 2
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| 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 |
23.12.2001 15-12-37.0 |
44 |
44 |
10 |
4 |
3.20/2 | | 4-4.5 | | IPC GS RAS | | 2 |
25.12.2001 06-03-01.9 |
43 |
44 |
10 |
6 |
3.7/3 | | 5 | | IPC GS RAS | |
| IPC GS RAS - Informational Processing Center, Geophysical Survey, Russian Academy of Sciences |
| Epicenter |
| Seismic stations of GS RAS in the period of December 22-26 have registered nearly 30 events.
Registered seismic activity is associated with Tersk-Sunzha rift zone, which is located within the area of Tersk-Caspian front deflection. This zone is characterized both by seismic activity being influenced by deep breaks of «Caucasian» direction – Middle, Sunzha (eastern extension of Pshekish-Tirniazsk break) and by diagonal junction zones, which are active in the modern time. This fact is confirmed by the earthquake, which has happened here on August 3, 1989 with magnitude 5.0. It was felt with intensity up to 7 MSK in the diagonal Benoisk-Eldarovsk junction zone, which is in 30 – 50 km to the East from the December 2001 origin place.
Table 2 contains parameters of other 10 events, which happened in this origin. They were obtained from data of local system of survey at KMW test area of CEME GS RAS: |
| Table 2 |
Date & Times (GMT)
yy-mm-dd hh:mm:sec | Latitude,
degr. | Longtitude,
degr. | Depth,
km | K | | 2001-12-22 10:35:49.6 | 43.65 | 44.70 | 10 | 8.8 | | 2001-12-23 7:29:3.2 | 43.78 | 44.70 | 25 | 10.2 | | 2001-12-23 11:43:54.5 | 44.16 | 44.53 | 17 | 8.4 | | 2001-12-23 11:45:59.7 | 44.21 | 44.60 | 13 | 9.1 | | 2001-12-23 12:41:39.6 | 43.81 | 44.67 | 20 | 9.8 | | 2001-12-23 12:46:25.4 | 44.07 | 44.64 | 15 | 8.6 | | 2001-12-23 12:50:9.7 | 43.96 | 44.54 | 9 | 8.9 | | 2001-12-23 13:33:2.0 | 43.88 | 44.55 | 5 | 8.5 | | 2001-12-23 13:45:18.5 | 43.92 | 44.64 | 19 | 8.8 | | 2001-12-23 15:16:33.5 | 43.88 | 44.63 | 23 | 9.0 |
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| Macroseismic manifestations |
| These earthquakes have happened on the border between Stavropol Region and Ingush Republic. According to the data of Northern Osetia MCHS division most sensitive earthquakes have been registered on December 23 at 15 hours 12 minutes and on December 25 at 06 hours 03 minutes. The first of them was felt in Mozdok (Ingush Republic) with intensity 3 MSK, the other one – in settlements Russkoe and Sernovodskoe (Kursk region of Stavropol) with intensity 4-5 MSK and in Mozdok – 3 MSK. Besides that the weak strikes have been felt in populated places within the whole period between 23 and 25 December 2001.
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