6.8 Earthquake Strikes India – Nepal Region18/09/2011
MON SEP 19 –
GANGTOK, India — Rescue teams battled landslides and torrential monsoon rains on Monday after a powerful earthquake rocked a vast and remote Himalayan region, killing at least 53 people in India, Nepal and Tibet.
The epicentre of Sunday’s 6.9-magnitude earthquake was in an isolated area of the border between India’s Sikkim state and Nepal, and there were fears the toll could rise as reports filtered in from distant towns and villages.
The heavy rains and low cloud grounded helicopter flights in the area, and Indian relief and rescue teams trying to access the Sikkim state capital, Gangtok, were blocked by landslides on the only viable highway.
SUN SEP 18 – UPDATED at 12:42 PM EST – The Guardian UK is reporting at least 9 people dead.
at 13:54 UTC 4.6 MAG aftershock: http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0005whe.php
at 13:11 UTC – 4.8 MAGNITUDE aftershock has struck same region – see USGS.gov -http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0005wgx.php
NEW DELHI (AP) 9:13 am 09.18.11— Officials say a strong earthquake has hit northeastern India near the border with Nepal. There were no immediate reports of damage or injuries.
Indian seismology official R.S. Dattatreyan says the quake struck Sunday evening and had a preliminary magnitude of 6.8. It was centered near Nepal in India’s northeastern state of Sikkim.
The state Meteorological department described the quake as of “moderate intensity” in UP. It has not ruled out the possibility of after shocks. Earlier, on September 7, tremors had hit some areas of UP adjoining Delhi. However, on Sunday no causality of any kind was reported till reports last came in. State Met director, JP Gupta said that after shocks can occur in next 24 hours.
The people in the Lucknow also felt the tremors for 30 seconds. Initially, people could not realise but later came out in open space leaving offices and home when they felt the tremors. The impact was more visible in the high rise buildings. But at some places, people did not feel anything and came to know about the quake later through news channels. Similar reports were received from Kanpur, Varanasi, Allahabad, Meerut and Gorakhpur.
Significantly, the city does not have any seismometer to record earthquake. A senior officer of the earthquake division, at the regional office of Geological Survey of India (GSI), Lucknow, said that they rely on data of the Meteorological department.
Geologist Dhruvsen Singh, also faculty in the department of geology in Lucknow University, said that there is no seismometer in the state anywhere to measure earthquake. In some research institutes, small seismometers have been installed purely for research. The geology department of Lucknow university also has a seismometer installed by National Geophysical Research Institute, Hyderabad, for research activity.
Singh said that the soil in UP, particularly in gangetic plain and in Lucknow, is loose alluvial soil, hence the possibility of epicenter of the quake in UP is less. The earthquake, he said, is a property of rocky unstable ground, which is not found in UP. “”Some east UP districts like Mirzapur have rocky ground but it is stable,”” he added. Singh, who was part of India’s first expedition to Artic, said that researches in UP so far have not shown any manifestation of tectonic activity.
Experts at GSI said earthquake occurs when two plates below the earth surface either rub or collide with each other. This at times create structural deformities known as “ridges” and “faults”, which can also cause tremors. There is also no record of an earthquake with epicentre in Lucknow. This is the reason, that Lucknow has been placed under Zone 3 (moderate risk zone), they added. “”Ttremors travel with a high velocity through rocks, causing extensive damage. However, their velocity reduces in loose segments. But with the retardation, the amplitude of waves increases as per the law of conservation of energy. High amplitude of the waves cause earth to vibrate vigorously, which can cause damage on the surface, particularly, if buildings in urban areas are not constructed as per laid down norms,”” they added.
Associated Press & Times of India