Information message about the strong earthquake near coast of New Britain, Papua New Guinea, March 29, 2015. |
| The strong earthquake M=7.2 has occurred on March 29, 2015 at 23:48 GMT (March 30, 02:48 Moscow time) near coast of New Britain, Papua New Guinea. |
| 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 14 min after
registration to the Ministry of Emergency of the Russian Federation (EMERCOM). |
| Preliminary processing has been done with data from 41 stations, accurate processing - with data 45 stations. |
| Fig. 1 presents fragments of records obtained from digital stations Port Moresby (∆ 7.2º), Tennant Creek (∆ 23.4º), Matsushiro (∆ 43.3º), Taejon (∆ 47.3º), Erimo (∆ 47.4º). Fig. 2 presents fragments of records obtained from digital stations Mys Shultsa (∆ 51º), Yuzhno-Sakhalinsk (∆ 52.2º), Severo-Kurilsk (∆ 55.3º), Petropavlovsk (∆ 57.8º), Magadan (∆ 64.2º).
|
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 |
23-48-28.6 |
-4.74 |
152.63 |
40 |
45 |
7.2/28 | 6.6/27 | 8-8.5 | 81 | IPC GS RAS (Accurate) | | 2 |
23-48-28.4 |
-4.75 |
152.68 |
40 |
41 |
7.2/24 | 6.6/23 | 8-8.5 | 81 | IPC GS RAS (Preliminary) | | 3 |
23-48-32.0 |
-4.75 |
152.62 |
40 |
294 |
Mw 7.5 | | | 11 | CSEM | | 4 |
23-48-31.2 |
-4.76 |
152.56 |
40 |
258 |
Mw 7.5 | | | 21 | 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, its origin was located in the Pacific Ocean, between the New Britain and New Ireland, Papua New Guinea, at a depth of 40 km, 63 km S-E of Kokopo, 82 km S-S-E of Rabaul, 294 km E-N-E of Kimbe and 321 km S-S-E of Kavieng. |
Figure 3 |
|
| Aftershock |
| GSRAS registered 10 aftershocks М>=4.8 within the day after the main shock. |
| 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 |
| 20151068 | 2015-03-30 00:15:28.0 | -5.12 | 152.67 | 33 | 35 | - | 5.7/ 19 | 5-5.5 | New Britain region, P.N.G. | | 20151069 | 2015-03-30 00:43:10.0 | -5.13 | 152.79 | 33 | 29 | - | 5.0/ 15 | 3.5-4 | New Britain region, P.N.G. | | 20151074 | 2015-03-30 04:16:11.0 | -5.32 | 152.54 | 33 | 30 | - | 5.3/ 19 | 4-4.5 | New Britain region, P.N.G. | | 20151075 | 2015-03-30 06:19:53.0 | -5.22 | 152.95 | 33 | 23 | - | 5.1/ 14 | 3.5-4 | New Britain region, P.N.G. | | 20151076 | 2015-03-30 06:58:23.0 | -5.44 | 153.06 | 33 | 22 | - | 4.9/ 13 | 3-3.5 | New Ireland region, P.N.G. | | 20151080 | 2015-03-30 08:31:44.0 | -4.67 | 152.53 | 33 | 36 | - | 5.3/ 21 | 4-4.5 | New Britain region, P.N.G. | | 20151083 | 2015-03-30 11:23:10.0 | -4.96 | 152.64 | 70 | 23 | - | 4.8/ 12 | 2 | New Britain region, P.N.G. | | 20151084 | 2015-03-30 11:43:19.0 | -5.3 | 153.17 | 33 | 27 | - | 5.2/ 14 | 4-4.5 | New Ireland region, P.N.G. | | 20151086 | 2015-03-30 14:52:10.0 | -5.13 | 152.84 | 33 | 27 | - | 5.2/ 13 | 4-4.5 | New Britain region, P.N.G. | | 20151092 | 2015-03-30 19:41:18.0 | -5.19 | 152.91 | 10 | 22 | - | 5.1/ 10 | 5.5-6 | New Britain region, P.N.G. | |
| Macroseismic manifestations |
| According to RIA-Novosti this earthquake caused a tsunami height of two feet in the port of Rabaul on the northeast coast of the island of New Britain.
Fig. 4 was obtained from USGS NEIC , it presents USGS Community Internet Community Map, based on 5 responses in 2 cities. |
Figure 4 |
|
| Focal mechanism and seismic moment of the earthquake |
| Focal mechanism solution was obtained in IPC GS RAS with signs of initial arrivals of P waves at 72 stations, including 54 of them which registered waves of compression (plus symbols) and 18 stations which registered tensile waves (minus symbols). These stations are located in the interval of epicentral distances of 0–99º and in azymuth sector Az=4-353º.
Focal solution of the origin in stereographical projection at the lower hemisphere is presented at fig. 5, elements of this solution are presented in table 2. Fig. 6, 7 present focal mechnism solutions obtained in USGS NEIC with W-phase Moment Tensor (Mww)technique and in Quick CMT Center with CMT technique. Elements of these solutions are presented in table 2. All solutions obtained in various centers are almost identical.
The motion has occurred under the action of compression strengths oriented to the south. Both nodal planes strike N-E–S-W (STK= 82º and 255-264º). NP1 plane lays more flat (DP=20ºи 32-33º) than NP2 (DP=57,58º and 70º). The type of motion for NP2 – reversed fault, for NP1 – reversed fault–transverse thrust with left latteral components of slip.
Seismic moment was obtained in IPC GS RAS with spectra of Р waves registered at the station «Talaya» (∆69.96º) Мо=1.7*10**20 N*m, Mw=7.4. According to USGS NEIC – Mo=2.469*10**20 N*m, Mw=7.5, according to CMT – Мо=1.72*10**20 N*m, Mw=7.4. |
| 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 |
| 77 | 348 | 13 | 173 |
1 | 82 | 264 | 32 | 92 | 82 |
58 | 89 | IPC GS RAS | | 65 | 357 | 25 | 170 |
2 | 262 | 255 | 20 | 83 | 82 |
70 | 93 | NEIC | | 78 | 354 | 12 | 170 |
1 | 261 | 259 | 33 | 89 | 81 |
57 | 91 | 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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