2007 Solomon Islands earthquake

2007 Solomon Islands earthquake

UTC time	??
Magnitude	8.1 Mw
Areas affected	Solomon Islands
Casualties	28

The 2007 Solomon Islands earthquake took place on April 2, 2007 near the island of Gizo, in the Solomon Islands. Its magnitude was calculated by the United States Geological Service (USGS) as being at 8.1 on the moment magnitude scale.

According to the USGS, the quake was recorded around 7:39 a.m. local time (6:40 a.m. EST in Australia) (UTC+11). The focus was Template:Unit km deep and Template:Unit km South South-East of Gizo township on New Georgia Islands.. Since the first earthquake there have been numerous aftershocks, the worst of which measured 6.2 on the moment magnitude scale.

Effects

At least twenty four people are reported to have been killed when a tsunami triggered by the earthquake struck the Solomon Islands, wiping out thirteen or more villages . Thousands were left homeless, and damages are estimated in millions. Rescuers are trying to reach other islands, and the reported death toll is thus expected to rise. In South Choiseul, waves 10 meters high swept away villages, gardens and a hospital. About 900 homes were destroyed and 5000 people left homeless .

The tsunami reached Papua New Guinea, with a family of five reportedly missing from a remote island in the tsunamis path.

Response

Areas affected by the main and aftershock earthquakes

A tsunami warning was issued for the South Pacific Ocean, and advisories issued for Japan and Hawaii. The Australian Bureau of Meteorology issued a warning for Australia's eastern coast, from Queensland's Barrier Reef to Tasmania, and beaches along the coast were closed, while many evacuated to higher ground. However, as the epicenter was close to the Solomon Islands, the tsunami hit before the Hawaiian Pacific Tsunami Warning Center released the warning.

High-magnitude ocean waves propagate at speeds near 25 meters per second, which means that they traverse the 25 kilometer distance from the epicenter to Gavo in 1000 seconds: less than 20 minutes. Fortunately, the S-waves from the earthquake shook the ground and alerted the population, allowing many to flee to high ground before the wave struck.

Aid Response

Australia has offered AU$2 million in aid, while New Zealand has offered NZ$500,000 and sent supplies in an air force plane.

Tectonic summary

The earthquake occurred along the boundary of the Pacific plate with, respectively, the Australia, Woodlark, and Solomon Sea plates. The latter three plates converge to the east-northeast or northeast against the Pacific plate with velocities of 90-105 mm/y. Along much of the plate boundary between the Pacific plate and the Australia/Woodlark/Solomon Sea plates, relative plate-motion is accomplished principally by subduction of the Australia/Woodlark/Solomon Sea plates beneath the Pacific plate. The April 2 earthquake's location and focal mechanism are consistent with the earthquake having occurred as underthrusting of the Australia/Woodlark/Solomon Sea plate beneath the Pacific plate, as part of the broader northeast-directed subduction process.

The Solomon Islands arc as a whole experiences a very high level of earthquake activity, and many shocks of magnitude 7 and larger have been recorded since the early decades of the twentieth century. The April 2 earthquake, however, nucleated in a 250km-long segment of the arc that had produced no shocks of magnitude 7 or larger since the early 20th century.

External links

• Stuff.co.nz:Tsunami fears after massive Solomons quake
• Associated Press: Tsunami hits Solomons
• Australian Bureau of Meteorology Tsunami Warnings summary
• NOAA - Solomon Islands - Historic Quakes
• Reuters - Solom Islands Tsunami Damage
• UNOSAT - Potential Tsunami Affected Areas
• Solomon Islands Government