Still reeling from a massive earthquake in April, Nepal just got hit with a devastating magnitude 7.3 aftershock. The latest earthquake is large enough to trigger its own sequence of aftershocks as stress redistributes around the ruptured fault line.
Top image: The recent M7.3 earthquake in Nepal is part of the same fault system as the April earthquake. Credit: USGS
When a fault ruptures during an earthquake, the stress along the portion of the fault that slipped is relieved while the stress at the locked ends increases. Located between Kathmandu and Mount Everest, today’s M7.3 and its aftershocks are far enough east of the older earthquakes that it appears a critical stress threshold was exceeded and the adjacent segment of the fault system ruptured. While unfortunate, this is not uncommon.
Cumulative damage is absolutely a problem with this latest earthquake. The intense shaking was a trigger to set off another round of landslides in the overly-steep terrain, further complicating transportation within the region. It was also enough to collapse already-damaged buildings, although thankfully the causalities from this latest disaster should be lower with people already evacuated from the previous earthquakes.