At least 42 people have been killed in and more than 1,000 others have been injured. Here’s why Nepal has been struck again and what to expect next.
What is an aftershock?
Large-magnitude earthquakes tend to be followed by several smaller magnitude earthquakes known as aftershocks.
Aftershocks look and act exactly the same as earthquakes, except that they are smaller than the mainshock and defined in their relation to the main event. The only difference is that an aftershock occurs in the same basic location, within an ‘aftershock zone’ and should occur before the rate of seismic activity returns to its pre-mainshock level.
Is Tuesday’s Nepal earthquake an aftershock?
Some aftershocks can occur on nearby faults outside the normal ‘aftershock zone’, but Tuesday’s quake could be seen as separate quake. Whereas the April quake’s epicenter was west of Kathmandu, the May 12 one struck east of the capital, near the Chinese border.
Tuesday’s quake has also sparked off another round of seismic jolts in its wake. Just 30 minutes after the 7.3 quake, an aftershock of 6.3 magnitude hit. There have been another five major aftershocks of magnitude 5.0 or higher.