The map shows the epicenter of the earthquake with a red marker, its origin was in the Pacific Ocean, SE of the Loyalty Islands, New Caledonia, at a depth of 10 km, 396 km E-SE of the port of Tadine, Mare Island, New Caledonia, 633 km E-SE of Noumea , capital of New Caledonia and 647 km S-SE of Port Vila, capital of Vanuatu.
|
Time in origin (GMT) |
Latitude, degree |
Longitude, degree |
Depth, km |
Stations number |
Ms/N |
mb/N |
I0 (calculated) |
GAP |
Center |
1
|
13:19:57.0
|
-22.75 |
171.5 |
10.0 |
41
|
7.1/29 |
6.5/22 |
10-10.5 |
192
|
GS RAS(Verified) Federal research center, Geophysical survey of Russian Academy of Sciences
|
2
|
13:19:59.6
|
-23.25 |
171.49 |
10.0 |
323
|
Mw 7.7 |
|
|
18
|
CSEM European - Mediterranean seismological center
|
3
|
13:19:55.9
|
-23.05 |
171.6 |
10.0 |
194
|
Mw 7.7/54 |
6.5/99 |
|
22
|
NEIC National Earthquakes Information Center of US Geological Service
|
Fig. 1 presents fragments of records obtained from digital stations Monsavu (∆ 7.9º), Stephens Creek (∆ 28º), Tennant Creek (∆ 34.7º), Matsushiro (∆ 66.8º), Taejon (∆ 72.1º). Fig. 2 presents fragments of records obtained from digital stations Yuzhno-Sakhalinsk (∆ 74.1º), Petropavlovsk (∆ 76.5º), Kuldur (∆ 79.9º), Magadan (∆ 83.8º), Yakutsk (∆ 90.6º).
Image 1
Image 2
GS RAS registered 3 foreshocks with М> = 5.4 within an hour before the main shock and 31 aftershocks with М> = 4.9 during the day after it.
N |
Time in origin (GMT) |
Latitude, degree |
Longitude, degree |
Depth, km |
Stations number |
Ms/N |
mb/N |
I0 (calculated) |
Region |
20210554
|
10/02/2021 12:24:21.0.0 |
-22.76 |
171.72 |
10.0 |
36 |
|
5.7/18 |
7-7.5 |
Southeast of Loyalty Islands
|
20210555
|
10/02/2021 12:32:10.0.0 |
-22.69 |
171.62 |
10.0 |
34 |
|
5.4/17 |
6-6.5 |
Southeast of Loyalty Islands
|
20210557
|
10/02/2021 13:01:59.0.0 |
-22.87 |
171.72 |
10.0 |
32 |
|
5.6/16 |
6.5-7 |
Southeast of Loyalty Islands
|
20210560
|
10/02/2021 13:57:17.0.0 |
-22.63 |
171.55 |
10.0 |
19 |
|
5.0/16 |
5-5.5 |
Southeast of Loyalty Islands
|
20210559
|
10/02/2021 14:18:19.0.0 |
-22.74 |
171.87 |
10.0 |
34 |
|
5.6/16 |
6.5-7 |
Southeast of Loyalty Islands
|
20210564
|
10/02/2021 14:30:23.0.0 |
-22.95 |
172.12 |
10.0 |
17 |
|
5.1/12 |
5.5-6 |
Southeast of Loyalty Islands
|
20210565
|
10/02/2021 14:37:21.0.0 |
-22.67 |
171.54 |
10.0 |
27 |
|
5.2/18 |
5.5-6 |
Southeast of Loyalty Islands
|
20210566
|
10/02/2021 14:49:56.0.0 |
-22.81 |
170.83 |
10.0 |
18 |
|
5.0/11 |
5-5.5 |
Southeast of Loyalty Islands
|
20210567
|
10/02/2021 14:59:37.0.0 |
-22.64 |
171.99 |
10.0 |
14 |
|
4.9/9 |
5-5.5 |
Southeast of Loyalty Islands
|
20210561
|
10/02/2021 16:35:21.0.0 |
-22.74 |
171.2 |
10.0 |
49 |
|
6.0/22 |
7.5-8 |
Southeast of Loyalty Islands
|
20210562
|
10/02/2021 17:25:49.0.0 |
-22.79 |
171.8 |
10.0 |
28 |
|
5.6/18 |
6.5-7 |
Southeast of Loyalty Islands
|
20210563
|
10/02/2021 18:36:40.0.0 |
-22.79 |
171.22 |
10.0 |
38 |
|
5.8/20 |
7-7.5 |
Southeast of Loyalty Islands
|
20210569
|
10/02/2021 19:56:14.0.0 |
-22.88 |
171.31 |
10.0 |
28 |
|
5.2/13 |
5.5-6 |
Southeast of Loyalty Islands
|
20210570
|
10/02/2021 20:45:13.0.0 |
-22.91 |
171.22 |
10.0 |
27 |
|
5.3/15 |
6-6.5 |
Southeast of Loyalty Islands
|
20210571
|
10/02/2021 21:23:59.0.0 |
-23.34 |
171.51 |
10.0 |
53 |
|
6.3/26 |
8.5 |
Southeast of Loyalty Islands
|
20210572
|
10/02/2021 21:40:33.0.0 |
-23.36 |
171.81 |
10.0 |
26 |
|
5.6/18 |
6.5-7 |
Southeast of Loyalty Islands
|
20210573
|
10/02/2021 21:49:58.0.0 |
-23.44 |
171.63 |
10.0 |
19 |
|
5.4/13 |
6-6.5 |
Southeast of Loyalty Islands
|
20210574
|
10/02/2021 21:57:10.0.0 |
-22.93 |
171.24 |
10.0 |
33 |
|
5.2/15 |
5.5-6 |
Southeast of Loyalty Islands
|
20210576
|
10/02/2021 22:03:42.0.0 |
-23.15 |
172.57 |
10.0 |
25 |
|
5.3/13 |
6-6.5 |
Southeast of Loyalty Islands
|
20210577
|
10/02/2021 22:38:00.0.0 |
-22.79 |
171.26 |
10.0 |
18 |
|
5.1/11 |
5.5-6 |
Southeast of Loyalty Islands
|
20210578
|
10/02/2021 22:54:17.0.0 |
-23.27 |
171.62 |
10.0 |
34 |
|
5.4/15 |
6-6.5 |
Southeast of Loyalty Islands
|
20210580
|
10/02/2021 23:26:27.0.0 |
-22.96 |
171.79 |
10.0 |
19 |
|
5.2/12 |
5.5-6 |
Southeast of Loyalty Islands
|
20210579
|
10/02/2021 23:32:46.0.0 |
-22.69 |
171.82 |
10.0 |
23 |
|
5.3/13 |
6-6.5 |
Southeast of Loyalty Islands
|
20210581
|
10/02/2021 23:45:14.0.0 |
-23.28 |
171.78 |
10.0 |
39 |
|
5.9/14 |
7.5-8 |
Southeast of Loyalty Islands
|
20210582
|
11/02/2021 00:14:45.0.0 |
-23.37 |
171.85 |
10.0 |
50 |
|
6.0/26 |
7.5-8 |
Southeast of Loyalty Islands
|
20210583
|
11/02/2021 01:02:03.0.0 |
-23.35 |
171.81 |
10.0 |
34 |
|
5.4/12 |
6-6.5 |
Southeast of Loyalty Islands
|
20210584
|
11/02/2021 01:24:39.0.0 |
-22.68 |
171.66 |
10.0 |
36 |
|
5.4/18 |
6-6.5 |
Southeast of Loyalty Islands
|
20210586
|
11/02/2021 04:15:16.0.0 |
-22.88 |
171.0 |
10.0 |
39 |
|
5.7/18 |
7-7.5 |
Southeast of Loyalty Islands
|
20210588
|
11/02/2021 06:52:32.0.0 |
-22.98 |
171.57 |
10.0 |
36 |
|
5.8/14 |
7-7.5 |
Southeast of Loyalty Islands
|
20210589
|
11/02/2021 07:18:40.0.0 |
-23.14 |
172.08 |
10.0 |
41 |
|
5.5/21 |
6.5-7 |
Southeast of Loyalty Islands
|
20210590
|
11/02/2021 07:56:03.0.0 |
-23.39 |
172.15 |
10.0 |
26 |
|
5.3/13 |
6-6.5 |
Southeast of Loyalty Islands
|
20210591
|
11/02/2021 08:22:09.0.0 |
-22.86 |
171.24 |
10.0 |
36 |
|
5.9/15 |
7.5-8 |
Southeast of Loyalty Islands
|
20210592
|
11/02/2021 08:39:12.0.0 |
-23.31 |
171.73 |
10.0 |
41 |
|
5.7/23 |
7-7.5 |
Southeast of Loyalty Islands
|
20210593
|
11/02/2021 11:19:25.0.0 |
-23.15 |
172.25 |
10.0 |
37 |
|
5.6/18 |
6.5-7 |
Southeast of Loyalty Islands
|
The focal mechanism solution of the origin was obtained in GS RAS with signs of initial arrivals of P waves at 45 stationsб including 31 stations which registered compression wavs (plus sign) and 14 stations which registered tensile waves (minus sign). These stations are located in the interval of epicentral distances of 7.9-99º and in azymuth sector Az=7-353º. The focal mechanism solution in stereographic projection at the lower hemesphere and it's elements are presented in the table. The table also presents focal mechanism solutions of the origin obtained in USGS NEIC with W-phase Moment Tensor (Mww) technique and in Lamont-Dohert Earth Observatory, Columbia University, USA (LDEO GCMT) obtained withу СМТ (Centroid moment tensor) technique. The earthquake occurred under the influence of a slight prevalence of compressive stresses oriented to the south (AZ=176-181º). One nodal plane NP1 strikes SW (STK=214º) according to GS RAS and W-SW (STK=246º) according to USGS NEIC and W (STK=279º) according to LDEO GCMT, another plane NP2 strikes E (STK=87-101º). NP1 plane lies flatter (DP=16-23º) if compared with NP2 (DP=67-84º). The type of motion along NP1 – left latteral slip accorfing to GS RAS and thrust according to USGS NEIC and LDEO GCMT, along NP2 – reverse fault. The seismic moment according to USGS NEIC Mo=4.364*10**20 N*m, Mww=7.7. According to LDEO GCMT Mo=4.01*10**20 N*m, Mw=7.7.
Axes of main strengths |
Nodal planes |
Center |
|
T |
P |
N |
NP1 |
NP2 |
PI: 49
Azm: 27
|
PI: 37
Azm: 178
|
PI: 14
Azm: 279
|
Stk: 214
Dp: 16
Slip: 24
|
Stk: 101
Dp: 84
Slip: 104
|
GS RAS Federal research center, Geophysical survey of Russian Academy of Sciences
|
|
PI: 60
Azm: 12
|
PI: 29
Azm: 176
|
PI: 7
Azm: 270
|
Stk: 246
Dp: 17
Slip: 65
|
Stk: 92
Dp: 75
Slip: 97
|
NEIC National Earthquakes Information Center of US Geological Service
|
|
PI: 67
Azm: 348
|
PI: 22
Azm: 181
|
PI: 4
Azm: 89
|
Stk: 279
Dp: 23
Slip: 101
|
Stk: 87
Dp: 67
Slip: 85
|
GCMT Lamont-Doherty Earth Observatory Global CMT Columbia University, USA
|
|