The Rise of 'Sonic Boom' Quakes: What Scientists Learned from Myanmar

Scientists are warning that "supershear" earthquakes - rare quakes that move faster than seismic waves - could cause more widespread destruction than previously thought. The warning follows the powerful 7.7 magnitude earthquake that struck Myanmar in March 2025, which scientists now believe was one such event.

What Are Supershear Earthquakes?

In a Seismological Research Letters paper, researchers from the University of Southern California's Dornsife College said supershear earthquakes move so rapidly that they outrun their own seismic shear waves, creating intense ground motion similar to a sonic boom.

"It breaks the shear wave speed barrier in the rocks and produces destructive waves that are stronger than what's generated by a normal earthquake," said Ahmed Elbanna, professor of earth sciences and director-designate of the Statewide California Earthquake Centre (SCEC), as per a report in Phys.org.

Lessons from Myanmar's Devastating Quake

A Reuters report said that the March 28, 2025, earthquake in Myanmar split the ground for over 460 kilometres (285 miles) - nearly twice what scientists expected for a quake of that magnitude.

"Preliminary studies indicate that the rupture was supershear," said Dr Judith Hubbard of Cornell University, adding that the rupture moved faster than seismic waves normally do.

This unusual speed is believed to have amplified the shaking, causing damage across vast distances, including structural failures reported as far away as Bangkok, Thailand.

California's Hidden Risk

In California, researchers say the danger of supershear events has been "greatly underappreciated."

"California is no more likely to have supershear earthquakes than other large fault regions," said Professor Yehuda Ben-Zion, director of SCEC. "But the threat has gone unnoticed for too long."

He warned that several magnitude 7 or higher earthquakes are expected in California over the next few decades, urging updates to hazard planning and building codes.

Current standards mainly prepare for shaking perpendicular to fault lines, but supershear quakes send their strongest energy along the fault, posing new risks to infrastructure.