April 2, 2007

tsunami in Solomon Islands

Following an earthquake measuring 8.1 on the Richter scale immediately off the coast of the Solomon Islands, scientists responded to reports of a large tsunami that had resulted in multiple fatalities.

Dr David Rothery, Senior Lecturer in Earth Sciences, The Open University, said:

“The tsunami-generating earthquake yesterday near the Solomon Islands was one of several known to have affected this region. The first tsunami wave would have reached Gizo Island within minutes of the quake itself, where several people lost their lives. People living on the coast so close to the earthquake’s epicentre need to ‘self-evacuate’ to higher ground as soon as they feel an earthquake, because earthquakes strike without warning and it takes time to determine whether or not a particular quake has triggered a tsunami.

“A tsunami warning was issued by the Pacific Tsunami Warning Center 15 minute after this quake, and was updated frequently over the next several hours in the light of measurements from tsunami warning buoys and other sources of information. The warning was cancelled when the initial waves had passed all vulnerable shores. In this instance, the height of the waves arriving decreased significantly with distance, and so waves arriving at shores beyond the Solomon Islands appear to have done little damage.”

Dr Carmen Solana Senior Lecturer in the School of Earth & Environmental Sciences, University of Portsmouth, said:

“The tsunami in Solomon Islands reinforces the role of education in preventing deaths. The magnitude 8 earthquake that hit Salomon Islands early this morning produced a medium size tsunami that hit the coast of many of the islands in the Solomon Archipelago.

“The Solomon islands are situated close to a very active subduction zone, where one plate sinks under another at great speed. The grounding between the two plates can produce very large earthquakes that occur very close to the sea floor (only 10 km) and this is the recipe for tsunamis to be produced. Geologically, the Salomon islands are very similar to that of the Andaman Islands where the Boxing Day tsunami occurred.

“When these large earthquakes occur close to the coast there is not time for warnings to arrive timely to the populations, that is why it is so important that everybody in the coastlines close to earthquake prone areas receive education on what can happen and instructions on what to do if they feel the earth trembling or they see the earth receding. They should quickly move to high ground and wait until they are instructed to go back. Tsunamis are very dangerous because of many waves can come with tens of minutes between them and the later ones are generally more destructive than the first ones.”

Dr Simon Boxall, Associate Lecturer, Southampton Oceanography Centre, Southampton University, said:

“This relatively mild but deadly earthquake has occurred on the Pacific “ring of fire”, one of the most geologically active areas on our planet and where most tsunamis are generated. The epicentre was unfortunately in the centre of the Solomon Islands and Gizo would have been hit by the wave within about 5 minutes of the initial quake – no time for any effective response. Whilst the effect has been devastating for this small chain of islands the power of the tremor and the resulting wave was localised; the energy being dispersed very rapidly causing no concerns for nearby Australia or Papua New Guinea.

“Perhaps the biggest tragedy is that these events have been occurring in this part of the Pacific for many years, with loss of life, and are the main reason for the very effective Tsunami warning system in place in this vast ocean. It is only since December 2004 that people worldwide, not just those on the Pacific Rim, appreciate the destructive power of a tsunami.”

Prof Bill McGuire, Director Benfield Hazard Research Centre, said:

“This part of the Pacific ‘Ring of Fire’ is geologically extremely active and volcanic eruptions and large submarine earthquakes are commonplace. It is not surprising that a major quake of this size should trigger a tsunami. The proximity of the quake to the Solomon Islands meant that there was no time to warn of the tsunami, which struck nearby coastlines within a few minutes, leading to a number of deaths. This sort of thing will continue to happen until populations living close to major earthquake faults are educated to self-evacuate inland or uphill immediately following strong ground shaking. Tsunami in the Pacific Ocean have claimed at least half a million lives over the last 2,000 years.”