Ring of Fire DISCOVERY: Earthquake in Indonesia was rare ‘SUPERSHEAR’ sparking SONIC BOOM

Normally, this would put a limit on most ruptures of approximately 1.8 miles per second (3km per second).

This is slightly slower than shear waves which typically move at around 2.5 to 3.1 miles per second (4km to 8km per second).

Supershear quakes are extremely rare, but have been observed a handful of times in recent history.

They are even thought to be behind the cataclysm that struck San Francisco in 1906.

If the deadly tremor that hit Indonesia last year was a supershear earthquake, it would go a long way to explain its intensity.

But there is one problem with the theory – the fault line behind the quake is not what’s expected of supershear structures.