Information message about the devastating earthquake near coast of Ecuador, April 16, 2016 |
| The devastating earthquake M=7.5 has occurred on April 16, 2016 at 23:58 GMT (April 17, 2:58 Moscow time) near coast of Ecuador. |
| 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 22 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 22 stations, accurate processing - with data 43 stations. |
| Fig. 1 presents fragments of records of digital stations Nana (∆ 12.6º), Albuquerque (∆ 42.4º), Pinyon Flat Observat. (∆ 47.6º), Lac Du Bonnet (∆ 51.6º), East Falkland Island (∆ 55º). Fig. 2 presents fragments of records of digital stations Sanae (∆ 86.3º), Kingsbay (∆ 90º), Lovozero (∆ 98.7º), Vasula (∆ 98.4º), Bilibino (∆ 98.3º). |
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 |
23-58-36.1 |
0.34 |
-79.93 |
20 |
43 |
7.5/30 | 6.8/17 | 9.5-10 | 61 | IPC GS RAS (Accurate) | | 2 |
23-58-42.2 |
2.33 |
-81.07 |
10 |
22 |
| 6.3/12 | 8.5-9 | | IPC GS RAS (Preliminary) | | 3 |
23-58-37.5 |
0.39 |
-79.91 |
20 |
469 |
Mw 7.8 | | | 27 | CSEM | | 4 |
23-58-37.3 |
0.37 |
-79.94 |
19.2 |
167 |
Mw 7.8 | | | 41 | 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 the epicenter of this earthquake, its origin was located on the N-W coast of Ecuador, at a depth of 20 km, 75 km S-S-W of Esmeraldas, 163 km N-N-E of Portoviejo, 170 km W-N-W of Quito, the Capital of Ecuador . |
Figure 3 |
|
| Aftershock |
| GS RAS registered foreshock 11 minutes before the main shock and 5 aftershocks М>=4.9 within 10 hours after it. |
| 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 |
| 20161381 | 2016-04-16 23:47:40.0 | 0.28 | -80.08 | 20 | 17 | - | 4.9/ 11 | 4-4.5 | Near coast of Ecuador | | 20161382 | 2016-04-17 00:29:29.0 | -0.27 | -80.51 | 10 | 30 | - | 5.4/ 14 | 6-6.5 | Near coast of Ecuador | | 20161383 | 2016-04-17 02:17:58.0 | -0.3 | -80.31 | 10 | 17 | - | 4.9/ 11 | 5-5.5 | Near coast of Ecuador | | 20161384 | 2016-04-17 04:02:06.0 | -0.25 | -80.56 | 10 | 14 | - | 4.9/ 9 | 5-5.5 | Near coast of Ecuador | | 20161386 | 2016-04-17 07:13:56.0 | -0.37 | -80.31 | 10 | 30 | - | 5.7/ 14 | 7-7.5 | Near coast of Ecuador | | 20161388 | 2016-04-17 09:23:38.0 | -0.29 | -80.69 | 10 | 22 | - | 5.5/ 10 | 6.5-7 | Near coast of Ecuador | |
| Macroseismic manifestations |
| According to ITAR-TASS 413 people were killed and more than two thousand injured. Among the dead in Ecuador there are citizens of Columbia and Canada. It destroyed a large number of buildings, severely damaged infrastructure settlements (Figure 4).The most severely affected by the earthquake are cities of Portoviejo, Manta and Pedernales.
The authorities of some countries in the region, including Mexico, Colombia and Salvador sent humanitarian aid, doctors, rescue workers and equipment to Ecuador. Pacific Tsunami Warning Center declared a tsunami alert, the height of the waves near coast of the department of La Libertad was 14 centimeters.
Fig. 5 was obtained from USGS NEIC, it presents USGS Community Internet Intensity Map based on 139 responses 36 cities. |
Figure 4 | 
Figure 5 |
|
| Historical records |
| January 31, 1906, an earthquake M=8.3, it was located 92 km N-E of the epicenter of this earthquake, then it caused a tsunami and killed from 500 to 1,500 people.
May 14, 1942, an earthquake M=7.8, it was located 40 km S of the epicenter of this earthquake. |
| Focal mechanism and seismic moment of the earthquake |
| Focal mechnism solution of the origin was obtained in IPC GS RAS with signs of initial arrivals of P waves at 85 stations, including 65 of them which registered compression waves (plus), and 20 stations which registered tensile waves (minus). These stations are located in the interval of epicentral distances 8.8–99.2º and in azimuth sector Az=0.6-357º. Focal mechanism in stereographic projection at lower hemisphere which was obtained by IPC GS RAS is presented in fig. 6, elements of this mechanism are presented in table.2. Fig. 7, 8 present focal mechanism solutions of the origin obtained in USGS NEIC with W-phase Moment Tensor (Mwс) technique and in Quick CMT Catalog Center, USA obtained with CMT technique. All solutions obtained in different centers are close, those obtained in USGS NEIC and Quick CMT are almost the same. According to USGS NEIC and Quick CMT this earthquake has occurred under prevailing action of compression stresses oriented to the west (AZ=271º) and tensile stresses oriented N-E (AZ=61º). Nodal plane NP1 is nearly vertical (DP=71º), it strikes S-S-E (STK=171º), NP2 – inclines to the horizon at an angle (DP=23º) and it strikes N-E (STK=26º). The type of motion in otigin for NP1 – reverse fault with left lateral slip component, for NP2 – thrust with right lateral slip component.
According to IPC GS RAS this earthquake has occurred under prevailing action of compression stresses oriented N-W and tensile stresses oriented N-E. Nodal plane NP1 is inclined to the horizon at a large angle (DP=73º), NP1 strikes to the south (STK=182º) , NP2 is inclined to the horizon at an angle (DP=33º), it strikes to the east (STK=64º). The type of motion of NP1 – reverse fault with left lateral slip component, NP2 right lateral slip with reverse fault component.
According to USGS NEIC – Mo=5.54*10**20 N*m, Mw=7.8; according to СМТ – Mo=5.53*10**20 N*m, Mw=7.8. |
| 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 |
| 53 | 57 | 23 | 294 |
28 | 191 | 182 | 73 | 81 | 64 |
33 | 148 | IPC GS RAS | | 62 | 60 | 25 | 271 |
12 | 175 | 171 | 71 | 77 | 26 |
23 | 123 | NEIC | | 62 | 61 | 25 | 271 |
12 | 175 | 171 | 71 | 77 | 26 |
23 | 123 | 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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