Seismic survey reveals new tsunami hazards around New Zealand
New Zealand scientists have discovered around 200 under-water fault lines capable of causing devastating tsunamis in a newly completed seismic survey around the country's coasts.
The discoveries brought the total number of known active fault sources in New Zealand waters to about 530, the National Institute of Water and Atmospheric Research (NIWA) announced Wednesday.
"We have to be prepared for these sorts of marine earthquakes in many New Zealand locations," NIWA principal scientist Dr Philip Barnes said in a statement.
NIWA had worked with the Institute of Geological and Nuclear Sciences (GNS Science) in a major revision of the New Zealand National Seismic Hazard Model to capture submarine faulting.
The new discoveries were largely attributed to the inclusion of the newly-identified offshore fault sources, including previously unknown faults in the bedrock under Pegasus Bay, off the earthquake-battered Canterbury region, where 185 people died in the city of Christchurch in the Feb. 22 quake last year.
A particularly large offshore fault was discovered during a seismic survey of 800 square kilometers in southern Pegasus Bay, shortly after the deadly earthquake.
"There are many earthquake faults on the seafloor around our coasts, and the next major earthquake could be centered offshore. So it highlights the need for coastal marine investigations of active earthquake faulting, for both ground-shaking hazards and tsunamis," said Barnes.
Some significant changes in possible earthquake hazards were observed, he said.
"If a major earthquake occurs on a seafloor fault, we might already have information about that fault," said Barnes.
In the last decade, many major earthquakes causing severe ground-shaking and tsunamis had occurred around the world, including the Boxing Day tsunami of 2004 that killed more than 200, 000 people and the quake off the northeast coast of Japan, which triggered massive tsunami waves in March last year.