Disaster waiting to happen?: Mount Merapi erupts hot lava as seen from Sleman, in Yogykarta province of Indonesia, 21 May 2006.
Credit: AFP
Rough estimate
The new results are part of the Geoscience Australia Natural Hazard Impacts Project and were prepared for the Australian government's overseas aid agency AusAID.
Data came from global earthquake catalogues and the Smithsonian Institution's Global Volcanism program. To calculate the risk, the researchers drew a rough circle around dormant volcanoes, representing the area that could be hit by ash fall of up to 30 cm in depth – enough to collapse a roof.
For earthquakes, the researchers looked at the probability a quake would occur at a distance close enough for ground motion to impact the city.
Cummins said it was a rough analysis because the calculations they used, such as the spread of ash fall, was in reality much more complex. But he added that it was important to give organisations some idea of what might reasonably be expected in the region.
Much of the Asia–Pacific region sits on the tectonic plate boundary between the Australasian and Indian plates and has seen some of the world's worst natural disasters.
"What's fairly new about the analysis is looking beyond the physical consequences of geological hazards and trying to get some idea of what the impacts might be on populations affected by natural disasters," said Cummins. "Infrastructure [in cities] can be very fragile and there are also very dense populations in some cities such as Dhaka, Jakarta, or Manilla."
