On Saturday, at 6:11 AM Coordinated Universal Time, a magnitude 7.8 earthquake occurred near Lamjung, Nepal. As of this writing, a national police spokesman has said 970 have died and over 1,700 have been injured.

BBC reports that deaths have been confirmed across India, Bangladesh, Tibet and Mount Everest, with at least 539 people killed in Nepal’s Kathmandu Valley alone. The United States has issued an initial $1 million in aid and has dispatched a disaster response team to Nepal.

The fault zone rupture appears to extend over 62 miles to the southeast. According to iO9, over 3.4 million people live within 47 miles of the earthquake’s epicenter.

Damage and casualties from the earthquake have been multiplied due to several regional as well as geologic factors. The hypocenter of the quake, the point within the earth where the earthquake begins, was located at 9.3 miles below the surface – a relatively shallow distance in geologic terms, which causes more intense shaking at the surface. The area affected by the quake contains a high population density, unstable slopes and buildings incapable of withstanding intense, prolonged shaking.

Several historic buildings have been destroyed, including the Dharahara Tower and Kathmandu’s Darbar Square, a UNESCO World Heritage site.

Nepal is located atop the tectonic convergence zone that gave birth to the Himalayan mountains. This is where the Indian and Eurasian plates meet. Rather than one plate sliding beneath another (the geologic term is “subducting”), the two plates push against each other at a rate just shy of a half-centimeter per year, forcing the ground upward into the spectacular mountain range visited by climbers from around the globe.

Image of the [] from the United States Geologic Survey.

Detail of the Lamjung rupture zone with the epicenter marked by a star.  Click to embiggen. (Image: USGS)

Unfortunately, this geologic wonder has its price: Convergent zones can produce massive earthquakes, and Nepal has experienced several in its history.

Little is yet known about the extent of this latest 7.8 earthquake. The country’s Information Minister Minendra Rijal has said that “massive damage” has occurred at the epicenter, and unstable infrastructure and aftershocks still pose risks to survivors. Casualty numbers are expected to climb in the coming hours and days.

In addition to the immediate damage from the earthquake, there is a high potential for subsequent landslides as soil is loosened and shifts over time. Slopes that aren’t dangerous now may become so during the region’s upcoming monsoon season.

Earlier today, Indian Prime Minister Narendra Modi tweeted, “We are in the process of finding more information and are working to reach out to those affected, both at home & in Nepal.”

According to the American Geophysical Union, it is highly likely that the worst news to come out of this disaster has not reached the public. As the AGU wrote in a blog post following the 2010 Haiti earthquake, “No news is very, very bad news. The biggest impacts are often in rural areas with the highest levels of shaking. These areas had poor communications to start with, but when an earthquake strikes the roads become blocked, power is lost and there is no telephone service.”

Planet Experts will follow this story as it develops.

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One Response

  1. Neil says:

    The images coming out of Nepal are harrowing. In 1934 — 81 years ago — more than 10,000 people died in a magnitude 8.1 earthquake in eastern Nepal. This is very similar to that.

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