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Information message about the activation of the seismic process off the coast of Kamchatka on July 20, 2025

A series of earthquakes occurred on July 20, 2025, off the coast of Kamchatka, the strongest at 06:49 GMT (09:49 Moscow Time) (catastrophic at the epicenter on the SIS-17 scale) with M=7.6. The development of the process was recorded starting with a foreshock at 06:02 with M=5.3, then at 06:28 with M=6.9. In total, five more earthquakes with magnitudes M>6 occurred within 40 minutes after the main shock along with the background weaker events.<br/> SIS-17 - Earthquakes. Seismic intensity scale. State Standard 57546–2017.

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 47 stations, accurate processing - with data from 81.

The red marker on the map is the epicenter of the earthquake, which was located in the Pacific Ocean off the E coast of Kamchatka, at a depth of 20 km, 137 km E of Petropavlovsk-Kamchatsky, 147 km E of Vilyuchinsk and 388 km NE of Severo-Kurilsk.

	Time in origin (GMT)	Latitude, degree	Longitude, degree	Depth, km	Stations number	Ms/N	mb/N	I0 (calculated)	GAP	Center
1	06:49:02.1	52.76	160.59	20.0	81	7.6/69	6.5/58	9.5-10	130	GS RAS(Verified) Federal research center, Geophysical survey of Russian Academy of Sciences
2	06:49:04.6	52.88	160.55	33.0	47		6.3/44	6.5-7		GS RAS(Preliminary) Federal research center, Geophysical survey of Russian Academy of Sciences
3	06:49:03.1	52.9	160.64	20.0	635	Mw 7.4	6.9/289		27	CSEM European - Mediterranean seismological center
4	06:49:01.3	52.91	160.79	10.0	168	7/455	6.5/1070		43	NEIC National Earthquakes Information Center of US Geological Service
5	06:48:58.9	52.6	160.95	4.8	10	Ml 7.2				KAGSR Kamchatka Regional Seismological Centre, Petropavlovsk-Kamchatskiy, Geophysical Survey, Russian Academy of Sciences

Fig. 1 presents fragments of records obtained from digital stations Petropavlovsk (∆ 1.2º), Severo-Kurilsk (∆ 3.5º), Magadan (∆ 8.9º), Seimchan (∆ 11.1º), Yuzhno-Sakhalinsk (∆ 12.9º). Fig. 2 presents fragments of records obtained from digital stations Bilibino (∆ 15.6º), Kuldur (∆ 18.4º), Yakutsk (∆ 18.9º), Zeya (∆ 19.9º), Mys Shultsa (∆ 22.1º).

Image 1

Image 2

GS RAS registered more than 50 events with a magnitude of M>4.2 within 12 hours since the beginning of the process activation. Events with a magnitude of M>5 are listed below. The earthquake at 06:28 was felt in Petropavlovsk-Kamchatsky with a magnitude of 4, Vilyuchinsk 3, and Elizovo 3 MSK.

N	Time in origin (GMT)	Latitude, degree	Longitude, degree	Depth, km	Stations number	Ms/N	mb/N	I0 (calculated)	Region
20253448	20/07/2025 06:02:50.0.0	52.77	160.66	20.0	64		5.3/38	5-5.5	Off east coast of Kamchatka
20253449	20/07/2025 06:28:17.0.0	52.98	160.42	20.0	91	6.9/61	6.2/61	8.5-9	Off east coast of Kamchatka
20253453	20/07/2025 07:02:09.0.0	52.83	160.79	20.0	32		5.4/18	5-5.5	Off east coast of Kamchatka
20253455	20/07/2025 07:06:24.0.0	52.67	160.29	20.0	36		5.4/21	5-5.5	Off east coast of Kamchatka
20253451	20/07/2025 07:07:43.0.0	52.67	160.67	20.0	65		6.4/38	7.5-8	Off east coast of Kamchatka
20253456	20/07/2025 07:13:00.0.0	52.86	160.68	20.0	62		6.1/36	7	Off east coast of Kamchatka
20253457	20/07/2025 07:18:56.0.0	52.87	160.84	20.0	33		5.3/15	5-5.5	Off east coast of Kamchatka
20253458	20/07/2025 07:23:00.0.0	52.91	160.67	20.0	56		6.3/33	7-7.5	Off east coast of Kamchatka
20253461	20/07/2025 07:26:19.0.0	53.05	160.82	20.0	54		6.2/29	7-7.5	Near east coast of Kamchatka
20253459	20/07/2025 07:36:28.0.0	53.02	160.81	20.0	21		5.1/12	4.5-5	Near east coast of Kamchatka
20253462	20/07/2025 07:53:24.0.0	52.81	160.7	20.0	39		5.2/20	4.5-5	Off east coast of Kamchatka
20253468	20/07/2025 09:30:54.0.0	52.74	160.61	20.0	55		5.2/43	4.5-5	Off east coast of Kamchatka
20253471	20/07/2025 10:03:40.0.0	52.97	160.77	20.0	48		5.5/29	5.5	Off east coast of Kamchatka
20253488	20/07/2025 15:03:51.0.0	52.42	160.45	20.0	45		5.4/36	5-5.5	Off east coast of Kamchatka
20253489	20/07/2025 15:32:27.0.0	52.36	160.46	20.0	61		5.7/39	6	Off east coast of Kamchatka
20253494	20/07/2025 15:43:15.0.0	52.34	160.81	20.0	34		5.1/21	4.5-5	Off east coast of Kamchatka
20253493	20/07/2025 15:44:34.0.0	52.31	160.54	20.0	56		5.7/38	6	Off east coast of Kamchatka
20253495	20/07/2025 16:14:00.0.0	52.39	160.53	20.0	48		5.6/34	5.5-6	Off east coast of Kamchatka

According to Kamchatka Branch of GS RAS the strongest earthquake was felt at 06:49 in Petropavlovsk-Kamchatsky with a magnitude of 5-6 MSK, in Nagorny with a magnitude of 5 MSK, in Vilyuchinsk, Elizovo with a magnitude of 4 MSK, in Severo-Kurilsk with a magnitude of 2-3 MSK, in Klyuchi with a magnitude of 2 MSK.

Click here to view detailed macroseismic data (DyfitWeb service)

Focal mechanism solution of the origin was calculated by GS RAS with signs of initial arrivals of P waves at 108 stations, including 74 stations which registered compression waves (plus signs), and 34 stations which registered tensile waves (minus signs). The stations are located in the interval of epicentral distances 1.2-86.2º and in azimuth sector Az=7-356º. 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 was caused by predominantly SE oriented compressional stresses (AZ=131-135º). One nodal plane NP1 strikes SW (STK=217-228º), another plane NP2 strikes NE (STK=42º-44º). NP1 is more horizontal (DP=19-24º) if compared with NP2 (DP=66-78º). The type of motion along NP1 – thrust, along NP2 – reverse fault. Seismic moment according to USGS NEIC makes Mo=1.374*10**20 N*m, Mww=7.36. According to LDEO GCMT it makes Mo=2.28*10**20 N*m, Mw=7.5.

Axes of main strengths			Nodal planes		Center
T	P	N	NP1	NP2	Center
PI: 64 Azm: 312	PI: 26 Azm: 135	PI: 1 Azm: 44	Stk: 228 Dp: 19 Slip: 94	Stk: 44 Dp: 71 Slip: 89	GS RAS Federal research center, Geophysical survey of Russian Academy of Sciences
PI: 69 Azm: 319	PI: 21 Azm: 132	PI: 2 Azm: 223	Stk: 217 Dp: 24 Slip: 84	Stk: 44 Dp: 66 Slip: 93	NEIC National Earthquakes Information Center of US Geological Service
PI: 57 Azm: 312	PI: 33 Azm: 131	PI: 0 Azm: 221	Stk: 219 Dp: 12 Slip: 88	Stk: 42 Dp: 78 Slip: 90	GCMT Lamont-Doherty Earth Observatory Global CMT Columbia University, USA

The Pacific Plate is moving W-NW relative to the North American Plate off the coast of Kamchatka in the zone of the reported seismic activity at a rate of about 77 mm/year. The location of the strongest earthquake and the nature of its movement are consistent with a fault on the plate boundary in the subduction zone of the Kuril-Kamchatka arc.
The strongest earthquake occurred 48 km E-SE of the strong earthquake of August 17, 2024 at 06:49 on the east coast of Kamchatka with a magnitude of M=7.3, 143 km E of the strong earthquake of April 3, 2023 on the east coast of Kamchatka with a magnitude of M=6.0 and 11 km W of the strong earthquake of December 23, 2023 on the east coast of Kamchatka with a magnitude of M=5.6.