The death toll is still rising from the powerful 7.9-magnitude earthquake – an extremely strong earthquake – in Nepal today (April 25, 2015). Hundreds are reported to have died from the quake so far, which wrecked many historic buildings. USGS originally reported the quake at a 7.5-magnitude and later upgraded this estimate. The quake took place at 6:11 UTC (1:11 a.m. CDT). This powerful quake’s tremors were felt across the region, and into neighboring India, Pakistan and Bangladesh. The quake struck between the capital Kathmandu and the city of Pokhara about 120 miles (200 km) away. At least one strong aftershock (6.6 magnitude) has already occurred, with many smaller aftershocks, and more are expected.
– Nepali minister reports “massive damage” at the epicenter.
– Eight bodies recovered from Mount Everest after an avalanche triggered by the quake in Nepal.
– The landmark Dharahara tower is among buildings reduced to rubble in Kathmandu.
Journalist Siobhan Heanue, of ABC News Australia, was in Kathmandu when the quake struck. She tweeted the following shocking before-and-after images:
I took these photos an hour apart. Was wandering when quake demolished temples before my eyes. Heartbreaking. pic.twitter.com/RYtIZI4725
— Siobhan Heanue (@siobhanheanue) April 25, 2015
The magnitude 7.9 earthquake that hit Nepal today was the result of a collision of great land plates on Earth. This process has caused deadly quakes in the past, including the 2005 Kashmir earthquake (7.6-magnitude) that killed over 80,000 people.
At the same time, according to USGS, just four events of magnitude 6 or larger have occurred within 150 miles (250 km) of the April 25, 2015 earthquake over the past century.
Details of the quake from USGS are as follows:
2015-04-25 06:11:26 (UTC)
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34km (21mi) ESE of Lamjung, Nepal
58km (36mi) NNE of Bharatpur, Nepal
73km (45mi) E of Pokhara, Nepal
76km (47mi) NW of Kirtipur, Nepal
77km (48mi) NW of Kathmandu, Nepal
Why do such powerful earthquakes occur in this region? Nepal sits on a part of Earth where one of our planet’s great land plates – called the India plate by scientists – is pushing beneath another (the Eurasia plate to the north). At the location of this earthquake, the India plate is converging with Eurasia at a rate of 45 mm/year towards the north-northeast, driving an uplift of the Himalayan mountain range. For example, Mount Everest – highest mountain on Earth – is still growing taller at a fraction of an inch (3-5mm) per year. USGS said:
The preliminary location, size and focal mechanism of the April 25 earthquake are consistent with its occurrence on the main subduction thrust interface between the India and Eurasia plates.
USGS also said that – although located at a major plate boundary with a history of large-to-great sized earthquakes – large earthquakes in this region are rare in the documented historical era.
Just four events of M6 or larger have occurred within 250 km of the April 25, 2015 earthquake over the past century. One, a M 6.9 earthquake in August 1988, 240 km to the southeast of the April 25 event, caused close to 1500 fatalities. The largest, an M 8.0 event known as the 1934 Nepal-Bihar earthquake, occurred in a similar location to the 1988 event. It severely damaged Kathmandu, and is thought to have caused around 10,600 fatalities.
Bottom line: A powerful earthquake struck Nepal – between the capital city of Kathmandu and Pokhara – at 6:11 UTC (1:11 a.m. CDT) on April 25, 2015. Hundreds dead and many historic buildings collapsed.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.