Information message about the strong earthquake near coast of Northern Chile April 1, 2014. |
| The strong earthquake with M=8 has occurred on April 1, 2014 at 23:46 GMT (April 2, 3:46 Moscow time) near coast of Northern Chile. |
| 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 23 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 25 stations, accurate processing - with data 31 stations. |
| Fig. 1 presents fragments of records obtained from digital stations Juntas de Abangares (∆ 32.6º), East Falkland Island (∆ 33.7º), Hockley (∆ 54.7º), Albuquerque (∆ 63.8º), Sanae (∆ 64.8º). Fig. 2 Fig. 1 presents fragments of records obtained from digital stations Pulkovo (∆ 112.3º), Obninsk (∆ 115.7º), Bilibino (∆ 119.9º), Kislovodsk (∆ 120.2º), Garni (∆ 121.7º). |
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 |
23-46-46.9 |
-19.6 |
-70.95 |
20 |
31 |
8/27 | 6.9/5 | 10-10.5 | 82 | IPC GS RAS (Accurate) | | 2 |
23-46-47.0 |
-19.47 |
-70.96 |
20 |
25 |
8/7 | 6.9/4 | 10-10.5 | 129 | IPC GS RAS (Preliminary) | | 3 |
23-46-49.7 |
-19.722 |
-70.863 |
33 |
140 |
Mw 8.0 | | | 129 | CSEM | | 4 |
23-46-46.5 |
-19.642 |
-70.817 |
20.13 |
114 |
Mw 8.2 | | | 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 epicenter of this earthquake which origin was located near coast of Northern Chile, at the depth of 20 km, 107 km N-W of Iquique, Chile, 185 km S-W of Tacna, Peru, and 450 km N-N-W of Antofagasta, Chile. The yellow star presents epicenter of the strong aftershock which origin was located near coast of Northern Chile, at the depth of 20 km, 117 km S-E of the main shock. |
Figure 3 |
|
| Aftershock |
| Increased seismic activity in this region was noticed since March 16, when it was recorded the earthquake at 21:16 GMT М=6.8 accopmpanied with minor magnitude aftershock registered on March 23 at 18:20 GMT М=6.3. After the shock М=8 GS RAS registered 18 aftershocks М>=4.9 and after 27 hours - the strongest shock М=7.6. Within 2 weeks nearly 50 events were registered near coast of Northern Chile. |
| 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 |
| 20141125 | 2014-04-01 23:57:57.0 | -19.55 | -70.46 | 10 | 14 | - | 5.9/ 4 | 7.5-8 | Near coast of Northern Chile | | 20141126 | 2014-04-02 00:24:44.0 | -19.96 | -71.02 | 10 | 20 | - | 5.3/ 3 | 6-6.5 | Off coast of Northern Chile | | 20141127 | 2014-04-02 00:33:44.0 | -20.42 | -70.95 | 10 | 15 | - | 5.3/ 2 | 6-6.5 | Near coast of Northern Chile | | 20141128 | 2014-04-02 00:37:46.0 | -19.76 | -70.87 | 10 | 8 | - | 5.1/ 3 | 5.5-6 | Near coast of Northern Chile | | 20141129 | 2014-04-02 01:20:57.0 | -19.52 | -70.94 | 10 | 15 | - | 5.3/ 4 | 6-6.5 | Near coast of Northern Chile | | 20141130 | 2014-04-02 01:29:39.0 | -19.96 | -70.94 | 10 | 18 | - | 4.9/ 3 | 5-5.5 | Near coast of Northern Chile | | 20141132 | 2014-04-02 03:40:15.0 | -19.78 | -71.09 | 10 | 15 | - | 5.0/ 4 | 5-5.5 | Off coast of Northern Chile | | 20141133 | 2014-04-02 04:46:18.0 | -20.25 | -70.95 | 10 | 25 | - | 5.4/ 4 | 6-6.5 | Near coast of Northern Chile | | 20141134 | 2014-04-02 05:02:50.0 | -19.73 | -71.34 | 10 | 16 | - | 5.2/ 3 | 5.5-6 | Off coast of Northern Chile | | 20141135 | 2014-04-02 06:04:10.0 | -19.88 | -71.19 | 10 | 16 | - | 5.0/ 4 | 5-5.5 | Off coast of Northern Chile | | 20141136 | 2014-04-02 06:29:15.0 | -20.12 | -70.83 | 10 | 24 | - | 5.2/ 6 | 5.5-6 | Near coast of Northern Chile | | 20141137 | 2014-04-02 08:25:50.0 | -20.22 | -70.97 | 10 | 19 | - | 5.0/ 4 | 5-5.5 | Near coast of Northern Chile | | 20141139 | 2014-04-02 11:07:32.0 | -20.04 | -71.01 | 10 | 25 | - | 5.4/ 3 | 6-6.5 | Off coast of Northern Chile | | 20141140 | 2014-04-02 11:11:34.0 | -19.96 | -71.18 | 10 | 21 | - | 5.0/ 3 | 5-5.5 | Off coast of Northern Chile | | 20141141 | 2014-04-02 13:00:56.0 | -19.8 | -70.82 | 10 | 17 | - | 5.1/ 3 | 5.5-6 | Near coast of Northern Chile | | 20141148 | 2014-04-02 19:45:48.0 | -20.27 | -70.71 | 10 | 26 | - | 5.3/ 4 | 6-6.5 | Near coast of Northern Chile | | 20141150 | 2014-04-03 00:01:17.0 | -19.81 | -71.33 | 10 | 13 | - | 5.1/ 2 | 5.5-6 | Off coast of Northern Chile | | 20141152 | 2014-04-03 01:58:29.0 | -20.26 | -70.61 | 10 | 21 | - | 6.1/ 4 | 8 | Near coast of Northern Chile | | 20141151 | 2014-04-03 02:43:13.0 | -20.5 | -70.46 | 20 | 26 | 7.6/ 8 | 6.9/ 5 | 9.5-10 | Near coast of Northern Chile | |
| Macroseismic manifestations |
| According to RIA-Novosti six persons were killed and three seriosly injured as a result of this earthquake accomponied with tsunami along the coast of Chile. Tsunami wave with height of 2 meters 11 sentimeters was observed in the area of Iquique. The waves with half meter height were observed in Peru. Earlier, the authorities announced the evacuation of the population in some coastal areas of Chile and Peru. Red alert level declared in the coastal areas of Ecuador. Warnings of a possible tsunami declared in Colombia, Panama, Costa Rica, El Salvador, Nicaragua.
A series of tsunami waves with height from 10 to 40 cm were registered on Thursday near Pacific coast of Japan. Tsunami wave with height of 40 centimeters reached Paramushiro Island of Northern Kurils. Small tsunami wave reached the coast of Sakhalin Island.
Fig. 4, presents USGS Community Internet Intensity Map, based on 70 responses in 1 ZIP code and 25 cities. |
Figure 4 |
|
| Historical records |
| This earthquake has occurred 1850 km N-N-E of destructive earthquake which happened on February 27, 2010 with М=8.7. More than 700 persons were killed after that earthquake accompanied with tsunami. More than 10000 persons were killed and 2 milion persons left homeless in the southern parts of Chile after the earthquake of May 22, 1960, which epicenter was located 2050 km N-N-E. That earthquake caused tsunami waves with height of 25 meters near epicenter of the earthquake. It is that earthquake among all the earthquakes of instrumental observation period which had the maximum magnitude of М=9.5 according to USGS NEIC |
| Focal mechanism and seismic moment of the earthquake |
| Focal mechanism was obtained in IPC GSRAS with signs of initial arrivals of P waves at 55 stations, including 38 stations which registered the waves of compression (plus signs) and 17 stations which registered the waves of expansion (minus signs). These stations are located in the interval of epicentral distances of 1–97º and are are evenly dispersed along the azimuths. Focal mechanism solution in stereographic projection at the lower hemisphere is presented at fig. 5, elements of mechanism are presented in table 2. Fig. 6, 7 and table 2 presents focal mechanism solutions of the origin obtained in USGS NEIC with tesor moment technique Mww and in Quick CMT Catalog, USA with CMT technique. Both solutions are close. This earthquake has ocсurred under the action of close in value stresses of compression and expansion oriented S-W and N-E respectively. Nodal plane NP1 in both solutions of these centers is dipping vertically (DP=73-83º), another plane NP2 is horizontal (DP=7–18º).
Both planes strike nearly along meridian: NP1 – (STK=157-172º), NP2 – (STK=2 – 357º). The type of motion for vertacal plane – reverse fault, for horizontal plane – strike slip.
According to USGS NEIC – Mo=2.35*10**21 N*m, Mw=8.2, according to Quick CMT – Mo=1.69*10**21 N*m, Mw=8.1. |
| 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 |
| 52 | 81 | 38 | 263 |
1 | 172 | 172 | 83 | 89 | 2 |
7 | 100 | IPC GS RAS | | 56 | 67 | 34 | 254 |
3 | 162 | 161 | 79 | 87 | 356 |
11 | 105 | NEIC | | 62 | 58 | 28 | 252 |
6 | 159 | 157 | 73 | 84 | 357 |
18 | 109 | 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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