Earthquakes across the world including powerful tremor in Ecuador and series of shakes in Japan could herald new MEGA quake, warns top scientist

Series of strong earthquakes prompt fears 'mega' earthquake could strike.

A scientist has warned that strain within the earth's crust could trigger it.

Four major earthquakes have struck 'Ring of Fire' region in the past week.

Two have struck Japan, another hit Ecuador and one occurred near Tonga.

A landslide destroyed part of a road in Minami, Japan after it struck the region yesterday. A scientist has warned the recent seismic activity could see a 'mega' earthquake in the future

Rescue workers in Minami, Japan work to clear trees and dirt from an area affected by the earthquake

It is feared 11 people in the region are missing and trapped under rubble and landslides caused by the quakes

'And if they delay, the strain accumulated during the centuries provokes more catastrophic mega earthquakes.'

In addition to the four major earthquakes to have struck since Thursday, last week there were also shakes in the Philippines, Vanuatu and Myanmar.

All of the earthquakes have occurred in countries straddling the so-called Ring of Fire.

This is a horseshoe-shaped series of trenches spanning the Pacific Ocean where tectonic plates are shifting and seismic and volcanic activity is common.

The U.S. Geological Survey, an independent agency which monitors natural hazards such as earthquakes, says 'mega' earthquakes are rare, but not impossible.

It says there is no fault line - the areas where shifting plates that make up the earth's crusts meet - is known which is capable of generating a magnitude 10 earthquake.

However, scientists cannot completely discount a 'mega' earthquake because they've only been measuring seismic activity for the past 100 years.

Meanwhile, Japanese rescue teams were today scouring the splintered remains of buildings destroyed by the shakes as time ran out for finding survivors.

Last night in Ecuador a major earthquake measuring 7.8 on the Richter scale hit last night, killing at least 77