A shallow quake but high magnitude

Published in The Hindu on September 1, 2012 The 7.6-magnitude quake that occurred at a depth of nearly 34 km below the ocean floor was due to the Pacific plate subducting (sinking) under the Philippines plate on the eastern side of Philippines. “From the seismologic point of view the earthquake is a shallow one,” said … Continue reading A shallow quake but high magnitude

April 11 quake: Distance from epicentre protects Indian cities

Published in The Hindu on April 13, 2012 If the amount of energy released during an earthquake is measured in terms of magnitude, its effects on the earth's surface are expressed in terms of intensity. Unlike magnitude that is determined using an instrument, intensity is measured only by effects felt by people. The one widely … Continue reading April 11 quake: Distance from epicentre protects Indian cities

Why the April 11 quake was caused by a strike-slip fault

Published in The Hind on April 13, 2012 Besides the subduction zone (where the Indian plate dives under the Burmese plate) that lies to the west of Indonesia, the Indian Ocean has a diffused seismicity zone. This zone lies to the west of the subduction zone. The east-west trending zone extends from 80 degree East … Continue reading Why the April 11 quake was caused by a strike-slip fault

Editorial: Lessons from Japan quake

Published in The Hindi on June 25, 2011 The 9 magnitude Tohoku-Oki earthquake that struck Japan on March 11, 2011, and triggered the deadly tsunami, was more powerful than expected. The magnitude of quakes in this region has been around 7-8 in recent centuries. Papers published recently in Nature and Science journals reveal why the … Continue reading Editorial: Lessons from Japan quake

Japan: why the killer quake was never expected

Published in The Hindu on June 23, 2011 The 9 magnitude Tohoku-Oki megathrust earthquake that rocked Japan on March 11 was caused by a sudden slip of the plate interface of a relatively small area of 400 km length and 200km width. That no seismologists had expected such a powerful quake to strike Japan (off … Continue reading Japan: why the killer quake was never expected

Editorial: The killer aftershock

Published in The Hindu on February 25, 2011 Barely six months after Christchurch, New Zealand's second largest city, was struck by a 7 magnitude earthquake, the city was the target of another quake of 6.3 magnitude on Tuesday. This one, the sixth aftershock of last year's tremor, turned out to be a killer. Prime Minister … Continue reading Editorial: The killer aftershock

Chile: where three tectonic plate boundaries meet

Published in The Hindu on March 4, 2010 The 8.8 magnitude earthquake had its epicentre in the Pacific Ocean about 115 km from Concepcion, Chile; it occurred at a depth of 35 km. This is not the first time that Chile has been struck by high magnitude earthquakes. The coast of Chile has witnessed 13 … Continue reading Chile: where three tectonic plate boundaries meet

Tsunami: role of mega thrust confirmed

Published in The Hindu on December 22, 2005 One year after the killer waves struck havoc that killed hundreds of thousands of people, the answers for what actually caused the tsunami have been documented by Discovery Channel. The study proved conclusively that it was a mega thrust — a large-scale rupturing and vertical displacement of … Continue reading Tsunami: role of mega thrust confirmed