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.
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.
An enormous 8.2 magnitude earthquake struck in the Pacific Ocean close to Fiji and Tonga on Sunday, but was too deep to cause any significant damage.
The quake's depth at 347.7 miles (560 km) would have dampened the shaking at the surface.
'We are monitoring the situation and some places felt it, but it was a very deep earthquake,' Director Apete Soro told Reuters.
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.
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.
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.