Sixty nine major earthquakes hit the Pacific's Ring of Fire in just 48 hours driving fears that the 'Big One' is about to hit California

• Sixteen tremors above magnitude 4.5 shook the Pacific 'Ring of Fire' on Monday
• This followed a cluster of 53 quakes that hit the geological zone on Sunday 
• The quakes rattled Indonesia, Bolivia, Japan and Fiji, but failed to reach the US
• Scientists have previously warned California is long overdue a major quake 

Sixty nine major earthquakes have hit Earth's most active geological disaster zone in the space of just 48 hours.

Sixteen 'significant' tremors - those at magnitude 4.5 or above - shook the Pacific 'Ring of Fire' on Monday, following a spate of 53 that hit the region Sunday.

The quakes rattled Indonesia, Bolivia, Japan and Fiji, but failed to reach the western coast of the United States, which also falls along the infamous geological ring.

The tremors have raised concerns that California's 'Big One' - a destructive earthquake of magnitude 8 or greater - may be looming.

Scientists have previously warned that Ring of Fire activity may trigger a domino effect that sets off earthquakes and volcanic eruptions elsewhere in the region.

California, which straddles the huge San Andreas Fault Line and sits on the eastern edge of the ring, is long overdue a deadly earthquake, researchers claim. 

Fears that a deadly earthquake may soon hit California have emerged after a swarm of quakes rocked one of Earth's major geological disaster zones. Pictured are the locations of 53 earthquakes above magnitude 4.5 that hit the Pacific Ring of Fire in just 24 hours on Sunday

The recent spate of Ring of Fire activity was recorded by experts at the United States Geological Survey, which is headquartered in Reston, Virginia.

Maps generated by the agency's vast array of seismometers shows Fiji was the worst hit, with five earthquakes above magnitude 4.5 - classed as 'significant' by the USGS - rumbling the country since Monday morning.

The largest of these was a 5.0 tremor that struck the region at 6:30am BST (1:30am ET) on Tuesday morning.A string of 16 quakes on Monday rattled Indonesia, Bolivia, Japan and Fiji, but failed to reach the western coast of the United States. Pictured are the locations of 'significant' earthquakes to hit the ring of Fire since Monday morning

Indonesia was hit by seven significant earthquakes, while the Soloman Islands, Bolivia and the Tonga were each rocked by a single quake, on Monday.

The nations often experience seismic activity as they sit along the Ring of Fire -a massive horseshoe-shaped area in the Pacific basin.

The ring is formed of a string of 452 volcanoes and sites of high seismic activity that encircle the Pacific Ocean, including the entire US west coast.

The (USGS) has not issued a warning over the recent shakes, meaning they do not pose an immediate risk to US citizens.

WHAT IS EARTH'S 'RING OF FIRE'?

Earth's so-called 'Ring of Fire' is a horseshoe-shaped geological disaster zone that is a hot bed for tectonic and volcanic activity.

Roughly 90 per cent of the world's earthquakes occur in the belt, which is also home to more than 450 volcanoes. 

The seismic region stretches along the Pacific Ocean coastlines, where the Pacific Plate grinds against other plates that form the Earth's crust.

It loops from New Zealand to Chile, passing through the coasts of Asia and the Americas on the way. 

In total, the loop makes up a 25,000-mile (40,000-kilometre) -long zone prone to frequent earthquakes and eruptions.

The region is susceptible to disasters because it is home to a vast number of 'subduction zones', areas where tectonic plates overlap.

Earthquakes are triggered when these plates scrape or slide underneath one another, and when that happens at sea it can spawn tsunamis. But the recent jump in Ring of Fire activity may spark activity elsewhere in the region, including California.

Professor Emily Brodsky, an Earth scientist at the University of California Santa Cruz, told Vox in February that volcanoes and earthquakes in the area 'can interact'. 

California was recently shaken by a cluster of 11 earthquakes, ranging in magnitude from 2.8 to 5.6 on the Richter scale.

The cluster occurred last month on the seabed at the Juan de Fuca tectonic plate, around six miles (10km) underwater off the US west coast.

This plate forms part of the Cascadia subduction zone, which runs from Northern California to British Columbia. 

The string of tremors has raised concerns that California's 'Big One' - a destructive earthquake of magnitude 8 or greater - may be looming. Pictured is the aftermath of the Northridge Earthquake, a 7.6 quake that struck the San Fernando Valley region of Los Angeles in 1994

Seismologists say a full rupture along the 650-mile-long (1,000 km) offshore fault could trigger a 9.0 magnitude earthquake and an accompanying tsunami.

Fears of a quake of this size, dubbed the 'Big One', were stirred last year by an expert who warned that a destructive earthquake will hit California 'imminently'.

Seismologist Dr Lucy Jones, from the US Geological Survey, warned in a dramatic speech that people need to act to protect themselves rather than ignoring the threat.

Dr Jones said people's decision not to accept it will only mean more suffer as scientists warn the 'Big One' is now overdue to hit California.

In a keynote speech to a meeting of the Japan Geoscience Union and American Geophysical Union, Dr Jones warned that the public are yet to accept the randomness of future earthquakes.

People tend to focus on earthquakes happening in the next 30 years but they should be preparing now, she warned.

HOW ARE EARTHQUAKES MEASURED?

The magnitude of an earthquake differs from its intensity.

The magnitude of an earthquake refers to the measurement of energy released where the earthquake originated.

Magnitude is calculated based on measurements on seismographs.

The intensity of an earthquake refers to how strong the shaking that is produced by the sensation is.

A 5.3 magnitude earthquake hit the Channel Islands off the coast of southern California on Thursday at 10.30am

According to the United States Geological Survey, 'intensity is determined from the effects on people, human structures and the natural environment'.

Earthquakes originate below the surface of the earth in a region called the hypocenter. 

During an earthquake, one part of a seismograph remains stationary and one part moves with the earth's surface.

The earthquake is then measured by the difference in the positions of the still and moving parts of the seismograph.