....WHAT HAPPENED? AND WHAT HAPPENS NEXT?
Seismologist Earle said the quake happened on what is known as a “thrust fault.” That describes the situation when one piece of the Earth’s crust is moving beneath another piece.
In this case, it’s the Indian plate that is moving north at 45 millimetres a year under the Eurasian plate to the north, Earle said. It’s a different type of earthquake than the one that caused the 1906 San Francisco earthquake.
“This is what builds the Himalayan mountain range,” Earle said.
The region and particular fault has a history of damaging earthquakes, including four temblors with magnitudes greater than 6.0 in the past 100 years, Earle said, warning that landslides are a particular worry now, given the steep slopes in the region.
Experts gathered in Nepal just a week ago to plan for giant quake !!!!!!!!!!!!!
Nepal's devastating earthquake was the disaster experts knew was coming.
out how to get this poor, congested, overdeveloped, shoddily built area to prepare better for the big one, a repeat of the 1934 temblor that leveled this city. They knew they were racing the clock, but they didn't know when what they feared would strike.
"It was sort of a nightmare waiting to happen," said seismologist James Jackson, head of the earth sciences department at the University of Cambridge in England. "Physically and geologically what happened is exactly what we thought would happen."
But he didn't expect the massive quake that struck Saturday to happen so soon. The magnitude 7.8 earthquake killed at least 1,180 people and caused widespread destruction.
"I was walking through that very area where that earthquake was and I thought at the very time that the area was heading for trouble," said Jackson, lead scientist for Earthquakes Without Frontiers, a group that tries to make Asia more able to bounce back from these disasters and was having the meeting.
A Kathmandu earthquake has long been feared, not just because of the natural seismic fault, but because of the local, more human conditions that make it worse.
The same size shaking can have bigger effects on different parts of the globe because of building construction and population and that's something the U.S. Geological Survey calculates ahead of time. So the same level of severe shaking would cause 10 to 30 people to die per million residents in California, but 1,000 maybe more in Nepal, and up to 10,000 in parts of Pakistan, India, Iran and China, said USGS seismologist David Wald.
While the trigger of the disaster is natural — an earthquake — "the consequences are very much man-made," Jackson said. Except for landslides, which in this case are a serious problem, "it's buildings that kill people not earthquakes," Jackson said. If you lived in a flat desert with no water, an earthquake wouldn't harm you, but then few people want to live there.
"The real problem in Asia is how people have concentrated in dangerous places," Jackson said.
Kathmandu was warned, first by the Earth itself: this is the fifth significant quake there in the last 205 years, including the massive 1934 one.
"They knew they had a problem but it was so large they didn't where to start, how to start," said Hari Ghi, southeast Asia regional coordinator for Geohazards International, a group that works on worldwide quake risks. Ghi, Jackson and Wald said Nepal was making progress on reducing its vulnerability to earthquakes, but not quickly or big enough.
Ghi's group on April 12 updated a late 1990s report summarizing the Kathmandu Valley risks.
"With an annual population growth rate of 6.5 percent and one of the highest urban densities in the world, the 1.5 million people living in the Kathmandu Valley were clearly facing a serious and growing earthquake risk," the report said, laying out "the problem" the valley faces. "It was also clear that the next large earthquake to strike near the Valley would cause significantly greater loss of life, structural damage, and economic hardship than past earthquakes had inflicted."
And for years there were no building codes and rampant development so homes and other structures could be built without any regards to earthquakes, the report said. There are now building codes, but that doesn't help the older structures, and the codes aren't overly strong, Ghi said.
Magnitude 7.9 earthquake hits Nepal: USGS
Agence France Presse
Posted at 04/25/2015 3:16 PM | Updated as of 04/25/2015 5:11 PM
KATHMANDU, Nepal - A powerful 7.9 magnitude earthquake struck Nepal on Saturday, the United States Geological Survey said, with strong tremors felt across the Himalayan nation and large parts of India and Bangladesh.
The quake struck 81 kilometers (50 miles) northwest of Kathmandu at 0611 GMT, with walls crumbling and families racing outside of their homes.
"The walls of houses have collapsed around me onto the road. All the families are outside in their yards huddled together. The tremors are still going on," an AFP reporter said in Kathmandu.
Initially measured at 7.5 magnitude, the quake was later adjusted to 7.9, with a depth of 15 kilometers, the USGS said. It hit 68 kilometers east of the tourist town of Pokhara.
Witnesses and media reports said the quake tremors lasted between 30 seconds and two minutes and were felt across the across the border in India, including in the capital New Delhi.
"We are in the process of finding more information and are working to reach out to those affected, both at home and in Nepal," Indian Prime Minister Narendra Modi said in a tweet.
The AFP office in Delhi was evacuated twice following the quake, a correspondent said.
Laxman Singh Rathore, director-general of the Indian Meteorological Department, told reporters that the impact had been felt across large swathes of northern India.
"The intensity was felt in entire north India. More intense shocks were felt in eastern UP (Uttar Pradesh) and Bihar, equally strong in sub-Himalayan West Bengal, Sikkim," he said.
Rathore that a second tremor of a 6.6 magnitude had been recorded around 20 minutes later and centered around the same region.
"Since it is a big earthquake, there are aftershocks and people should stay cautious," he said.
"The damage potential of any earthquake above seven magnitude is high. The duration of the earthquake tremors was different at different places. It was around 50-55 seconds long in Delhi."
The earthquake was also felt across large areas of Bangladesh, triggering panic in the capital Dhaka as people rushed out onto the streets.
In the garment manufacturing hub of Savar, on the outskirts of Dhaka, at least 50 workers were injured after the quake set off stampede in a garment factory, according to private Jamuna television.
A 6.9-magnitude quake hit northeastern India in 2011, rocking neighboring Nepal and killing 110 people.
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USGS Map of the Nepal earthquak