Three earthquakes in four days: What you need to know

Both Japan and Ecuador are on the seismically active "ring of fire" around the Pacific Ocean. Here is a brief look at the events.

Three earthquakes hit Japan and Ecuador in a span of four days.

The first quake, measuring 6.2 on the Richter Scale, struck an area in the north of Kumamoto City in South Japan at 9.26 pm JST on April 14. The second quake — stronger and more intense than the first one — struck Kumamoto City at 1.25 am in the wee hours of Saturday, April 16.

That same day, though several time zones apart, Ecuador felt the brunt of a big 7.8 magnitude quake at 8 pm local time. At least 238 people have been reported dead and the number is likely to rise.

Here is a brief look at the events.

Both Japan and Ecuador are on the seismically active “ring of fire” around the Pacific Ocean. Japan's 2011 quake and tsunami killed nearly 20,000 people. According to the U.S. Geological Survey, this region has seen some of the largest earthquakes in the world, including the largest earthquake on record, the 1960 M 9.5 earthquake in southern Chile.

It is also home to over 75 per cent of the world’s active and dormant volcanoes.

Photo courtesy: Wikimedia Commons

The epicentre of Saturday's quake was near the city of Kumamoto and measured at a shallow depth of 10 km (six miles), the United States Geological Survey (USGS) said. The shallower a quake, the more likely it is to cause damage.

Ecuador's quake was shallow as well, being only 19.2 kms deep. Seven magnitude 7 or greater earthquakes have occurred within 250 km of this event since 1900, according to USGS.

(Compiled by Janane Venkatraman with inputs from Agencies)