Credit: Image courtesy of Costas Synolakis
On September 28, 2018, an inexplicably large tsunami devastated the Indonesian coastal city of Palu and several others nearby. Between the tsunami and the magnitude 7.5 earthquake that caused it, some 4,340 people were killed, making it the deadliest earthquake that year.
The tsunami’s waves reached around six meters high, which was a shock to geophysicists who had believed that earthquakes along a strike-slip fault could only trigger far smaller tsunamis for that particular region. Now, new research describes a mechanism for these large tsunamis to form, and suggests that other coastal cities that were thought to be safe from massive tsunamis may need to reevaluate their level of risk.