The marker on the map is the epicenter of the earthquake, its origin was in northern Chile at a depth of 120 km, 40 km SE of San Pedro de Atacama, 110 kilometers from the city of Calama and 300 km E-NE of Antofagasta.
|
Time in origin (GMT) |
Latitude, degree |
Longitude, degree |
Depth, km |
Stations number |
Ms/N |
mb/N |
I0 (calculated) |
GAP |
Center |
1
|
01:50:48.0
|
-23.11 |
-67.93 |
120.0 |
55
|
|
7.3/13 |
7-7.5 |
118
|
GS RAS(Verified) Federal research center, Geophysical survey of Russian Academy of Sciences
|
2
|
01:50:46.5
|
-23.15 |
-67.81 |
100.0 |
14
|
|
6.9/3 |
|
|
GS RAS(Preliminary) Federal research center, Geophysical survey of Russian Academy of Sciences
|
3
|
01:50:48.8
|
-23.08 |
-67.81 |
128.0 |
724
|
7.4 Mw |
|
|
11
|
CSEM European - Mediterranean seismological center
|
4
|
01:50:47.7
|
-23.05 |
-67.78 |
117.4 |
105
|
7.4 Mw |
|
|
29
|
NEIC National Earthquakes Information Center of US Geological Service
|
Fig. 1 presents fragments of records obtained from digital stations Las Campanas (∆ 6.3º), Nana (∆ 13.9º), East Falkland Island (∆ 29.5º), Las Juntas de Abangares (∆ 37.1º), Новолазаревская (∆ 65º). Fig. 2 presents fragments of records obtained from digital stations Lovozero (∆ 115.9º), Obninsk (∆ 116.9º), Kislovodsk (∆ 120.3º), Khabaz (∆ 120.4º), Garni (∆ 121.5º).
Image 1
Image 2
Focal mechanism solution of the origin was calculated by GS RAS with signs of initial arrivals of P waves at 80 stations, including 25 stations which registered compression waves (plus signs), and 55 stations which registered tensile waves (minus signs). The stations are located in the interval of epicentral distances 0.4-98.3º and in azimuth sector Az=3-357º. Focal mechanism solution in stereographic projection on the lower hemisphere and elements of the mechanism are presented in the table. The table also contains focal mechanism solutions obtained at the USGS NEIC with WW-phase Moment Tensor (Mww) technique and in Lamont-Dohert Earth Observatory of Columbia University, USA (LDEO GCMT) with СМТ (Centroid moment tensor) technique. Solutions from different centers are close. The earthquake occurred under prevailing action of tensile stresses oriented E-NE (AZ=66-74º). One nodal plane NP1 strikes S-SE (STK=165-167º) according to GS RAS and LDEO GCMT and S (STK=172º) according to USGS NEIC, another plane NP2 strikes N-NW (STK=332-344º). NP1 lies more horizontally (DP=20-24º) if compared with NP2 (DP=66-71º). The type of motion along NP1 – gentle fault, along NP2 – normal fault. The seismic moment according to USGS NEIC makes Mo=1.444*10**20 N*m, Mww=7.4. according to LDEO GCMT it makes Mo=1.24*10**20 N*m, Mw=7.3.
Axes of main strengths |
Nodal planes |
Center |
|
T |
P |
N |
NP1 |
NP2 |
PI: 25
Azm: 66
|
PI: 64
Azm: 234
|
PI: 5
Azm: 334
|
Stk: 167
Dp: 20
Slip: -76
|
Stk: 332
Dp: 71
Slip: -95
|
GS RAS Federal research center, Geophysical survey of Russian Academy of Sciences
|
|
PI: 24
Azm: 74
|
PI: 66
Azm: 244
|
PI: 4
Azm: 342
|
Stk: 172
Dp: 21
Slip: -80
|
Stk: 341
Dp: 69
Slip: -94
|
NEIC National Earthquakes Information Center of US Geological Service
|
|
PI: 21
Azm: 74
|
PI: 69
Azm: 252
|
PI: 1
Azm: 344
|
Stk: 165
Dp: 24
Slip: -89
|
Stk: 344
Dp: 66
Slip: -91
|
GCMT Lamont-Doherty Earth Observatory Global CMT Columbia University, USA
|
|