Earthquake of magnitude 6.1 strikes Myanmar-India border region: EMSC

• A shallow and strong earthquake of magnitude 6.1 struck the Myanmar-India border region.
• The quake was felt in Chittagong in Bangladesh and as far away as Kolkata, according to witness accounts posted on European-Mediterranean Seismological Centre’s (EMSC) website .

Earthquake:

• An earthquake in simple words is the shaking of the earth. It is a natural event. It is caused due to release of energy, which generates waves that travel in all directions.
• The vibrations called seismic waves are generated from earthquakes that travel through the Earth and are recorded on instruments called seismographs.
• The location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicenter.
• Types of Earthquake: Fault Zones, Tectonic Earthquakes, Volcanic Earthquake, Human Induced Earthquakes.

How Do We Measure Earthquakes?

• The energy from an earthquake travels through Earth in vibrations called seismic waves. Scientists can measure these seismic waves on instruments called seismometer.
• A seismometer detects seismic waves below the instrument and records them as a series of zig-zags.
• Scientists can determine the time, location and intensity of an earthquake from the information recorded by a seismometer.
• This record also provides information about the rocks the seismic waves traveled through.

Seismic Hazard Map of India

• India is one of the highly earthquake affected countries because of the presence of technically active young fold mountains - Himalaya.
• India has been divided into four seismic zones (II, III, IV, and V) based on scientific inputs relating to seismicity, earthquakes that occurred in the past and tectonic setup of the region.
• Previously, earthquake zones were divided into five zones with respect to the severity of the earthquakes but the Bureau of Indian Standards (BIS) grouped the country into four seismic zones by unifying the first two zones.
• BIS is the official agency for publishing the seismic hazard maps and codes.

Seismic Zone II:

• Area with minor damage earthquakes corresponding to intensities V to VI of MM scale (MM-Modified Mercalli Intensity scale).

Seismic Zone III:

• Moderate damage corresponding to intensity VII of MM scale.

Seismic Zone IV:

• Major damage corresponding to intensity VII and higher of MM scale.

Seismic Zone V:

• Area determined by pro seismically of certain major fault systems and is seismically the most active region.
• Earthquake zone V is the most vulnerable to earthquakes, where historically some of the country’s most powerful shocks have occurred.
• Earthquakes with magnitudes in excess of 7.0 have occured in these areas, and have had intensities higher than IX.