Nepal earthquake: A time to rethink

Date: April 26, 2015

Seismic zones of India Mercalli intensity scale Richter scale P-waves

Earthquake Devastated Nepal, Killing More than 2,300

A powerful earthquake shook Nepal on Saturday near its capital, Katmandu, killing more than 2,300 people, flattening sections of the city’s historic center, and trapping dozens of sightseers in a 200-foot watchtower that came crashing down into a pile of bricks. It was a high-intensity earthquake of magnitude 7.8 on the Richter scale had struck central Nepal between its capital Kathmandu and the city of Pokhara.

Earthquake’s epicenter was 80 kilometers east of Pokhra near Kathmandu. It had a depth of only 11 kilometers (7 miles) i.e. in geological terms it was a shallow depth. The eartquake intensity was very high and caused that much destruction due to shallow depth.

The effects of this earth quake were also felt in north Indian states of Bihar, Jharkhand, Uttar Pradesh, Rajasthan, Assam, Delhi, Madhya Pradesh, West Bengal, Haryana, and Punjab. The tremors were also reported in Pakistan and Bangladesh.

Brief Introduction of Earthquake-

Earthquakes can be recorded by seismometers up to great distances, because seismic waves travel through the whole Earth's interior. The absolute magnitude of a quake is conventionally reported by numbers on the moment magnitude scale/ Richter scale, whereas the felt magnitude is reported using the modified Mercalli intensity scale (intensity II–XII).

Every earthquakes produces different types of seismic waves, which travel through rock with different velocities:

           Longitudinal P-waves (shock- or pressure waves)
           Transverse S-waves (both body waves)
           Surface waves — (Rayleigh and Love waves)

Seismic zones of India-