Information message about the earthquake in the North-West of Iran on June 22, 2002 |
| On June 22, 2002 the strong destructive earthquake has taken place in the North-Western part of Iran. It happened in 06 hours 58 minutes Moscow time (02 hours 58 minutes GMT). |
| 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 32 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 14 stations, accurate processing - with data 35 stations. |
| Figure 1 contains fragments of records for vertical component (BHZ) at digital stations, which were obtained by IPC in a close to real time mode: Obninsk (delta 21 degrees), Arti (delta 22 degrees), Pulkovo (delta 27 degrees), Kongberg, Norway (delta 35 degrees), Talaya (delta 42 degrees). Figure 2 contains records of vertical component (BHZ) from digital stations YAK (delta 55 degrees), Magadan (delta 66 degrees), Bilibino (delta 67 degrees), South-Sahalinsk (delta 67 degrees), Petropavlovsk-Kamchatka (delta 73 degrees).
|
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: |
| Note: (main strike, aftershocks and map of epicenters) are presented on the Iranian site The International Institute of Earthquake Engineering and Seismology (IIEES) |
| 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 |
02-58-20.70 |
35 |
49 |
10 |
35 |
6.40/18 | 6.40/10 | 9-9.5 | | IPC GS RAS (accurate) | | 2 |
02-58-23.8 |
35 |
48 |
33 |
4 |
6.5/8 | 6.2/8 | 7-7.5 | | IPC GS RAS (preliminary) | | 3 |
02-58-30.1 |
36 |
48 |
33 |
223 |
| 6.3 | | | CSEM | | 4 |
02-58-21.0 |
35 |
48 |
10 |
72 |
6.4/57 | 6.3/82 | | | 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 |
| Macroseismic manifestations |
| The earthquake has taken place on June 22 in Iran, in its North-Western part. Two dozens of villages were located in the earthquake’s epicenter, more than half of their houses were destroyed. The strikes were so strong, that they were felt in Teheran, which is located at the distance of 130 km to the East from epicenter. The number of victims of the earthquake exceeded 500 men, nearly two thousands were wounded and 25 thousands of people became homeless. The biggest number of victims was in the region of Buin Sahara town of Kasvin province.
|
| Focal mechanism and seismic moment of the earthquake |
| Solutions of focal mechanism of the earthquake 22.06.2002 calculated with TMC method in HARVARD center (USA) are presented in table 2 and shown on figure 3.
Focal mechanism of the earthquake on June 22, 2002 from HARVARD data (fig.3).
As it is seen, the solutions obtained by different centers are close to each other. The earthquake has taken place under the action of compression strengths, oriented in the South-South-Western direction. Both nodal planes have North-Western-Latitudinal direction, the type of motion along both planes – thrust.
The value of seismic moment Мо calculated from Р-wave spectra at Obninsk station made 9.0*10**26 D*CM.
The value of seismic moment Мо calculated from Р-wave spectra at Talaya station made 4.1*10**25 D*CM. The value of moment magnitude made Mw =6.6.
The value of seismic moment Мо obtained from TMC method in NEIC and HARVARD, made 6.9*10**25 D*CM and 7.1*10**25 D*CM respectively. The value of moment magnitude from data of NEIC made Mw =6.5, HARVARD - Mw =6.5 .
|
| 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 |
| 79 | 73 | 7 | 200 |
9 | 291 | 280 | 39 | 76 | 117 |
52 | 101 | NEIC | | 68 | 354 | 20 | 199 |
9 | 106 | 304 | 26 | 110 | 102 |
66 | 80 | HARVARD | |
| NEIC - National Earthquakes Information Center of US Geological Service |
| HARVARD - Harvard Geophysical Center (USA) |
Figure 3 |
|
