Expert proposes better use of satellites for disaster management

Japan: Norihiro Sakamoto proposed a plan to make better use of existing satellites so that they could make quicker tsunami forecasts. This would involve using a quasi-zenith satellite system, whereby a satellite is always located near Japan's zenith, so that there is a continuous link with offshore tsunami observation devices.

Norihiro Sakamoto, the former head of technology at the Society of Japanese Aerospace Companies, currently serves as a researcher for the Tokyo Foundation and has been advocating development of a "real-time warning system" for tsunami.

To prepare for a disaster when communication networks and satellite dishes are forced offline because of tsunami-related damage, an idea has been floated of building an "ultra-large deployable satellite dish" that can conduct satellite communication through cell phone networks.

This system would usually use a satellite dish located on land, but will be able to conduct communication via satellites in the event of an emergency.

"If a space utilisation system that could issue quicker tsunami warnings had been in place, the deaths of half the victims of the [March 11, 2011] disaster could have been prevented," Sakamoto said.

This disaster has also prompted reviews of ground observation systems.

The Japan Meteorological Agency wrongly estimated the Great East Japan Earthquake had a magnitude of 7.9, considerably lower than its actual size of 9. This meant it predicted a tsunami with a maximum height of six meters in Miyagi Prefecture and three meters in Fukushima and Iwate prefectures. This forecast was much lower than the actual height of the tsunami and was a major cause of the delay in evacuating these areas. This miscalculation occurred because the formula used by the agency to measure quakes cannot accurately measure an earthquake with a magnitude of 8 or stronger.

To rectify this situation, the government has begun a project to create an "emergency tsunami warning system" that will be able to make direct tsunami observations and will be able to forecast the height of waves when they hit the coast.

This would be the tsunami equivalent of the earthquake warning system that makes rapid forecasts on earthquake intensities throughout the nation, based on their initial tremors.

In developing the system, the government is planning to lay cable-connected seismographs and tsunami gauges from fiscal 2012. They will be placed on the sea floor at 150 locations off Nemuro, eastern Hokkaido, to areas off the Boso Peninsula, Chiba Prefecture.

Along the Nankai Trough, a deep trench in the Pacific Ocean of Shikoku where a magnitude-9 earthquake is predicted, the number of observation devices will be increased from seven to 15 by the Japan Coast Guard.

When the project is completed, it will be possible to make detailed measurements of the amount of seismic energy accumulated on the borders of tectonic plates that have collided in the trough.

The Cabinet Office is also going to start studying countermeasures against large-scale volcanic disasters that have not taken place recently, but are forecast to eventually occur in Japan.

To reduce the impact of natural disasters on the Japanese archipelago, it is imperative to expand the nation's space and underwater surveillance networks.

Publishing Date: 

07/02/2012
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