B Basnet ,(The Kathmandu Post)
KATHMANDU, Jan 3 ,2009-
The government has installed 24 Global Positioning System (GPS) stations across the country in order to monitor tectonic movement and identify earthquake-prone zones, said officials at the National Seismological Centre (NSC).
According to the officials, GPS stations were installed to monitor tectonic movement -- shifting of the earth's upper mantle -- which causes earthquakes in the Himalayan region.
"We completed GPS installation in October. These stations will help us identify earthquake-prone zones," said NSC chief Som Sapkota.
The stations will provide valuable information about the changes in the earth's layers and help us alert the government about potential danger, he said.
Experts say Nepal should be prepared for a high-magnitude earthquake, one potentially measuring 7 or more on the Richter scale. "The NSC also excavated at four places in Dhangadi and Mahottrari districts to find out the frequency of earthquakes in the past. This will help us know when earthquakes are likely to jolt particular regions," said Sapkota.
The NSC chief added that the discovery of earthquake frequency in a region is the most crucial information that can help minimise loss of life and property. Sapkota also informed that the NSC would produce a seismic hazard map soon.
Experts say Nepal lies in one of the most active seismic zones in the world. After the Indian subcontinent collided with the Tibetan Plateau some 45 million years ago, it has continued to drive under the plateau at a rate of two metres per century. This movement creates pressure between the landmasses. The pressure is released rapidly and results in earthquakes. Earthquakes frequently rattle Nepal. According to Dilli Ram Tiwari, survey officer at the NSC, Nepal experiences 10 small-scale earthquakes on average per day. He said most earthquakes are, however, rated under 4 on the Richter scale.
Earthquakes measuring over 4.8 on the Richter Scale are hazardous, he said. Nepal experienced its last destructive earthquake in 1934. It had the magnitude of 8.3. Experts say there will be massive loss of life and properties if an earthquake with 7-plus magnitude rocks the Kathmandu Valley.
According to National Society for Earthquake Technology-Nepal (NSET), the kind of soil in the Valley strongly influences the amount of damage caused during earthquakes. The valley is filled with soft sediment, as it rests on the bed of a prehistoric lake. Soft sediment amplifies the energy released by an earthquake at a greater degree than dense sediment does, causing greater damage.
(Collected by :Er. Pradeep )
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