Categorized | Earthquake, News

Very strong 7.7 magnitude quake strikes near Russia, no tsunami threat

Magnitude
7.7
Date-Time
Tuesday, August 14, 2012 at 02:59:42 UTC
Tuesday, August 14, 2012 at 12:59:42 PM at epicenter
Monday, August 13, 2012 at 04:59:42 PM (HST) – Hawaii Standard (Honolulu)
Location
49.784°N, 145.126°E
Depth
625.9 km (388.9 miles)
Region
SEA OF OKHOTSK
Distances
158 km (98 miles) ENE of Poronaysk, Russia
226 km (140 miles) ENE of Shakhtersk, Russia
236 km (146 miles) ENE of Uglegorsk, Russia
243 km (150 miles) ESE of Aleksandrovsk-Sakhalinskiy, Russia

TSUNAMI BULLETIN NUMBER 001
PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS
ISSUED AT 0309Z 14 AUG 2012

THIS BULLETIN APPLIES TO AREAS WITHIN AND BORDERING THE PACIFIC OCEAN AND ADJACENT SEAS…EXCEPT ALASKA…BRITISH COLUMBIA… WASHINGTON…OREGON AND CALIFORNIA.

… TSUNAMI INFORMATION BULLETIN …

THIS BULLETIN IS FOR INFORMATION ONLY.

THIS BULLETIN IS ISSUED AS ADVICE TO GOVERNMENT AGENCIES. ONLY NATIONAL AND LOCAL GOVERNMENT AGENCIES HAVE THE AUTHORITY TO MAKE DECISIONS REGARDING THE OFFICIAL STATE OF ALERT IN THEIR AREA AND ANY ACTIONS TO BE TAKEN IN RESPONSE.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME – 0300Z 14 AUG 2012
COORDINATES – 49.7 NORTH 145.3 EAST
DEPTH – 582 KM
LOCATION – SEA OF OKHOTSK
MAGNITUDE – 7.3

EVALUATION

A DESTRUCTIVE TSUNAMI WAS NOT GENERATED BASED ON EARTHQUAKE AND HISTORICAL TSUNAMI DATA.

THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT UNLESS ADDITIONAL INFORMATION BECOMES AVAILABLE.

THE JAPAN METEOROLOGICAL AGENCY MAY ALSO ISSUE TSUNAMI MESSAGES FOR THIS EVENT TO COUNTRIES IN THE NORTHWEST PACIFIC AND SOUTH CHINA SEA REGION. IN CASE OF CONFLICTING INFORMATION… THE MORE CONSERVATIVE INFORMATION SHOULD BE USED FOR SAFETY.

THE WEST COAST/ALASKA TSUNAMI WARNING CENTER WILL ISSUE PRODUCTS FOR ALASKA…BRITISH COLUMBIA…WASHINGTON…OREGON…CALIFORNIA.

USGS: How large does an earthquake have to be to cause a tsunami?

Magnitudes below 6.5
Earthquakes of this magnitude are very unlikely to trigger a tsunami.

Magnitudes between 6.5 and 7.5
Earthquakes of this size do not usually produce destructive tsunamis. However, small sea level changes may be observed in the vicinity of the epicenter. Tsunamis capable of producing damage or casualties are rare in this magnitude range but have occurred due to secondary effects such as landslides or submarine slumps.

Magnitudes between 7.6 and 7.8
Earthquakes of this size may produce destructive tsunamis especially near the epicenter; at greater distances small sea level changes may be observed. Tsunamis capable of producing damage at great distances are rare in the magnitude range.

Magnitude 7.9 and greater
Destructive local tsunamis are possible near the epicenter, and significant sea level changes and damage may occur in a broader region.

Note that with a magnitude 9.0 earthquake, the probability of an aftershock with a magnitude exceeding 7.5 is not negligible. To date, the largest aftershock recorded has been magnitude 7.1 that did not produce a damaging tsunami.

2 Responses to “Very strong 7.7 magnitude quake strikes near Russia, no tsunami threat”

  1. AH says:

    USGS today publishes magnitude as — 7.7

    • Baron says:

      Just updated the magnitude. The USGS usually corrects the preliminary magnitude to a final recorded one fairly quickly but this one appeared to be problematic. Two temblors were listed at one point, both with the preliminary magnitude (this is common as different instruments will record it as separate events with a delay). I’m glad it wasn’t larger.

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