ID :
205647
Wed, 09/07/2011 - 04:30
Auther :
Shortlink :
https://oananews.org//node/205647
The shortlink copeid
Japan to Introduce Seismometers Resilient to Strong Jolts
Tokyo, Sept. 6 (Jiji Press)--The Japan Meteorological Agency plans to introduce new seismometers at 80 locations nationwide that do not go off the scale even when giant earthquakes strike, sources told Jiji Press on Tuesday.
The move comes after some seismometers installed by the agency went off the scale when the magnitude-9.0 quake hit northeastern Japan on March 11. As a result, the agency was late in grasping the scale of the megaquake and revising an initially issued tsunami warning.
It plans to seek funds for the installation of the new seismometers under the government's planned third supplementary budget for the current fiscal year ending in March 2012, the sources said.
The agency's existing seismometers are not designed to measure quakes of over 8.0 magnitude.
The conventional seismometers worked properly during the magnitude-7.3 quake that devastated the western city of Kobe and nearby areas in January 1995.
But the March 11 megaquake was beyond the measuring range of the devices, prompting the agency to develop and introduce new ones that can measure long-period seismic waves and are not excessively sensitive to strong jolts.
Quake readings by seismometers are used to forecast the maximum height of tsunamis that follow.
Three minutes after the March quake occurred, the agency estimated its magnitude at 7.9. Based on this reading, it issued a warning that a tsunami of up to 6 meters would hit.
If the seismometers had worked properly, the agency would otherwise have revised the initial tsunami warning after gathering more accurate data about the tremor.
In fact, the agency was forced to reassess the maximum height of the tsunami based on wave movements observed off the Pacific coast. About 28 minutes after the quake struck, the agency issued a revised warning that a tsunami of 10 meters or higher would hit.
If the seismometers had worked accurately, the agency could have issued an updated tsunami alert about 15 minutes after the quake, cutting the wait time almost in half, according to officials of the agency.
The agency also plans to strengthen its tsunami-monitoring system.
By combining these measures, the agency intends to improve its tsunami-warning system, the officials said.
The move comes after some seismometers installed by the agency went off the scale when the magnitude-9.0 quake hit northeastern Japan on March 11. As a result, the agency was late in grasping the scale of the megaquake and revising an initially issued tsunami warning.
It plans to seek funds for the installation of the new seismometers under the government's planned third supplementary budget for the current fiscal year ending in March 2012, the sources said.
The agency's existing seismometers are not designed to measure quakes of over 8.0 magnitude.
The conventional seismometers worked properly during the magnitude-7.3 quake that devastated the western city of Kobe and nearby areas in January 1995.
But the March 11 megaquake was beyond the measuring range of the devices, prompting the agency to develop and introduce new ones that can measure long-period seismic waves and are not excessively sensitive to strong jolts.
Quake readings by seismometers are used to forecast the maximum height of tsunamis that follow.
Three minutes after the March quake occurred, the agency estimated its magnitude at 7.9. Based on this reading, it issued a warning that a tsunami of up to 6 meters would hit.
If the seismometers had worked properly, the agency would otherwise have revised the initial tsunami warning after gathering more accurate data about the tremor.
In fact, the agency was forced to reassess the maximum height of the tsunami based on wave movements observed off the Pacific coast. About 28 minutes after the quake struck, the agency issued a revised warning that a tsunami of 10 meters or higher would hit.
If the seismometers had worked accurately, the agency could have issued an updated tsunami alert about 15 minutes after the quake, cutting the wait time almost in half, according to officials of the agency.
The agency also plans to strengthen its tsunami-monitoring system.
By combining these measures, the agency intends to improve its tsunami-warning system, the officials said.
