SOPAC: REDUCING THE IMPACT OF DISASTERS

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SOUTH PACIFIC APPLIED GEOSCIENCE COMMISSION (SOPAC) Suva, Fiji Islands

PRESS RELEASE April 7, 1999

REDUCING THE IMPACT OF DISASTERS

By Russell Howorth, SOPAC Program Manager

In the past few weeks there have been two significant activities, in my mind at least, on the agenda for improving the well being of communities in the Pacific in regard to the impact of disasters. One was taking place offshore of the north coast of Papua New Guinea, while the second was in St. Lucia in the Caribbean.

Along the north coast of Papua New Guinea, the events of the evening of July 17th 1998 will live long in the memories of those that survived, and at the same time almost certainly lost close family. The tsunami that struck the Sissano area was totally destructive.

A total of three tsunami waves, with cumulative amplitude of 15 meters, inundated the coast leaving a trail of death and destruction. Over 2,000 people died, three villages were obliterated and four more badly damaged.

To a geologist a tsunami, or seismic sea wave, is like many other natural processes occurring on the Earth which may cause death and destruction when people and property get in the way. Of vital importance to the geologist is to be able to study these most unfortunate events when they do occur in order to understand them better. This in turn will lead to better disaster preparedness and mitigation planning, and ultimately reduction in risk, relief and recovery costs.

The tsunami is believed to have resulted from a 7.1 magnitude earthquake that was located in the Sissano vicinity, although the exact position remains uncertain despite the monitoring of aftershocks using seismometers deployed in the area affected.

The immediate response from the international scientific community was to send a team to assess the on-land effects of the tsunami. Their survey indicated the maximum wave height along the Sissano Lagoon spit to be 15 meters. The difficulty was that the initial computer simulation studies based upon a magnitude 7.1 earthquake only partly recreated the tsunami magnitude and wave-height distribution along the coast.

To simulate the tsunami and to understand how and why it had taken place, data on the offshore seabed morphology and geology were required. It was likely that there had been a strong focusing effect from the local seabed morphology. Had the seabed been disrupted, and if so how? Had there been a massive submarine landslide? Many questions were being asked.

The South Pacific Applied Geoscience Commission (SOPAC) as the organization with responsibility for regional geohazards and disaster management initiatives, on behalf of the Government of Papua New Guinea, secured the commitment of the Japan Marine Science and Technology Center(JAMSTEC) to fully support, organize and carry out two collaborative SOPAC/JAMSTEC surveys offshore of the devastated area. In acknowledgment of JAMSTEC's willingness to provide an almost instant and positive response it should be noted that surveys of this nature usually take several years to plan and implement.

The first survey using the research vessel Kairei took place in early January 1999, remarkably in less than six months of the disaster occurring. The survey area was located offshore of Sissano and it provided a very detailed picture of an area hitherto unknown.

The main equipment onboard the Kairei was a SEABEAM 2112 multibeam system, which produces bathymetric and side-scan sonar image maps of the sea floor. Onboard data processing delivered the bathymetry as the survey proceeded. Additionally, high-resolution, sub-bottom seismic profile data, piston cores of sediments beneath the seabed and gravity and magnetic data were acquired. Because of safety requirements the ship surveyed only in water depths greater than 200 meters. In total, over 25,000 square kilometers of seabed were mapped. Four piston cores approximately 8 metros long each were acquired.

From the regional bathymetry data collected on the first cruise, an area just offshore of Sissano Lagoon was selected for detailed survey by unmanned submersible remotely operated vehicle (ROV), the Dolphin-3K capable of diving to water depths of 3000 metros. This second two-week survey, completed on March 2nd, using the research vessel Natsushima, acquired visual images of the seabed. The images were recorded on video and by still camera. Additionally, rock and sediment samples were acquired.

The results of the two surveys are still being processed and interpreted.

Of course as with much work of this nature, exploring previously unknown areas of the ocean and seabed, the data gathered raises as many questions as are answered. One of the most important uses of the data is in the computer simulation of the tsunami. Preliminary survey results show the tsunami computer simulations are becoming more realistic. The focusing effect of the bottom morphology was very significant indeed. The visual observation of the seabed provides important information on tsunami processes and is prompting the modelers to modify their ideas about tsunami source mechanisms.

At the same time as the second cruise was underway in Papua New Guinea, on the other side of the world in St. Lucia in the Caribbean there was a conference on small states organized by the World Bank and Commonwealth Secretariat. At that conference a session was held on catastrophe insurance and disaster risk/management. An advanced proposal for the Caribbean small states, most of which are small island states like the Pacific, was presented.

The proposal essentially provides for government-sponsored funding of a reinsurance pool through access to international markets and with support of the World Bank. Primary insurance responsibility would remain with the private sector, but higher level risks for natural disasters would be reinsured with this pool instead of the international reinsurance markets.

Such a reinsurance pool should stabilize insurance premiums which have a habit of rising dramatically after disasters or are simply non-existent. Pacific representatives to that meeting agreed with the World Bank that developing a similar scheme for the Pacific was timely. Further consideration is likely to be given to this at the Forum Economic Ministers Meeting scheduled for Apia in early July.

At the SOPAC Governing Council meeting in November 1982, I reported that distribution of losses through insurance or other financial methods was just one approach to reducing impact of disasters. Other options included avoidance, by careful selection of areas to live, land use zoning, and engineering design. Furthermore, notwithstanding these options an improved understanding of the natural processes that lead to the disasters was vital. Implementing effective strategies is taking place, albeit slowly, through activities such as the South Pacific Disaster Reduction Project which started only six years ago and is now based at SOPAC, and the Pacific Cities Project which began three years ago at SOPAC. This World Bank offshore reinsurance initiative is yet another initiative.

We must surely all applaud these separate but intimately linked initiatives at Sissano and St. Lucia. They provide a reminder that maybe the time is not far away for the communities of the small island Pacific states to have a real expectation of improved well being in regard to disasters. On the one hand an increased understanding of the processes that cause disasters will lead to improved preparedness and risk reduction, and at the same time an appropriate financial mechanism to buffer the huge costs involved with recovery is being developed.

For more details, please contact: Russell Howorth

SOPAC Program Manage Tel: 381-377 or E-mail: russell@sopac.org.fj

SEE: http://www.sopac.org.fj/cruises/sissano.asp

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