Powerful Earthquake Strikes Tonga

Earthquake Measuring Up to M 7.1 Strikes Near NUKU’ALOFA, Tonga

A powerful earthquake measuring up to 7.1 Mw struck  about 135 km (85 miles) ENE of NUKU’ALOFA, Tonga at a depth of 10 km on  November 24, 2009 at 12:47 UTC.

The quake was followed by at least two aftershocks, the stronger of which measured up to 5.8 Mw.

Tsunami Evaluation:

The Pacific Tsunami Warning Center/NOAA/NWS Evaluated the Tsunami Hazard as follows:

NO DESTRUCTIVE WIDESPREAD TSUNAMI THREAT EXISTS BASED ON HISTORICAL EARTHQUAKE AND TSUNAMI DATA.

HOWEVER – EARTHQUAKES OF THIS SIZE SOMETIMES GENERATE LOCAL TSUNAMIS THAT CAN BE DESTRUCTIVE ALONG COASTS LOCATED WITHIN A HUNDRED KM OF THE EARTHQUAKE EPICENTER. AUTHORITIES IN THE REGION OF THE EPICENTER SHOULD BE AWARE OF THIS POSSIBILITY AND TAKE APPROPRIATE ACTION.

FEWW Comment: Does the SW Pacific region including Tonga, Fiji, and Samoan Islands regions act as a ‘planetary seismic shock damper?’  How much longer will the service last?

10-degree Map Centered at 20°S,175°W

Earthquake location Map. Source: USGS/EHP. Enhanced by FEWW.

Earthquake Details:

• Magnitude: 6.8  [Maximum quake magnitude estimated at 7.1 Mw by FEWW]
• Date-Time:
  • Tuesday, November 24, 2009 at 12:47:14 UTC
  • Wednesday, November 25, 2009 at 02:47:14 AM at epicenter
• Location: 20.641°S, 174.068°W
• Depth: 10 km (6.2 miles)
• Region: TONGA
• Distances:
  • 135 km (85 miles) ENE of NUKU’ALOFA, Tonga
  • 220 km (135 miles) S of Neiafu, Tonga
  • 480 km (300 miles) E of Ndoi Island, Fiji
  • 2100 km (1300 miles) NE of Auckland, New Zealand
• Location: Uncertainty horizontal +/- 5.6 km (3.5 miles); depth fixed by location program
• Source:  USGS NEIC (WDCS-D)
• Event ID: us2009pja1

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