A series of deadly earthquakes struck the Indonesian island of Lombok over three weeks in August 2018, causing widespread damage. These earthquakes were unusual because there were two magnitude-6.9 mainshock events that were each preceded by a smaller foreshock, instead of a single mainshock. The complexity of the earthquake sequence caused great anxiety about when another powerful earthquake might occur.

In our study published in the journal Science Advances, we demonstrate how the complexity of this earthquake sequence is due to the influence of Gunung Rinjani, Lombok’s large active volcano, on the geological fault that hosted the earthquakes.

After the first powerful magnitude-6.4 earthquake...

In conversation with Assistant Professor Aron Meltzner, Principal Investigator at the Earth Observatory of Singapore

1. How does the recent powerful magnitude-7.8 earthquake in Alaska remind us of similar hazards in Southeast Asia?

Last week, we saw a powerful earthquake off the coast of Alaska with a magnitude of 7.8 which had the potential to trigger a damaging tsunami, but fortunately this did not happen.

It occurred along a subduction zone where the Pacific Plate is subducting or slipping under the North American plate. The shaking that we know as an earthquake results from the sudden movement between these two plates, but that sudden movement also has the potential to lift up the seafloor, which in turns lifts the water above it, and that can...

Just after 6pm on 28 September 2018 (Singapore time), a magnitude-7.5 earthquake struck central Sulawesi. The powerful quake generated a tsunami which, along with massive landslides, devastated Palu and the town of Donggala. These resulted in more than 4,000 people dead or missing.

In an economic loss assessment report issued by Indonesia's National Disaster Management Agency (BNPB), the Palu earthquake event caused more than S$1.5 million in damages.

Today, a year later, scientists from the Earth Observatory of Singapore (EOS) and their teams are ready to share some of their findings about this earthquake-tsunami event.

Using a combination of seismic, geodetic, geologic, and written records, Assistant Professor Wei...

On 5 July 2019 at 1.33am (Singapore time), a Mw 6.4 earthquake struck the town of Ridgecrest in California. Its seismic waves could be felt from Los Angeles to San Jose. Nearly a day and a half later, on 6 July at 11.19am (Singapore time), a more powerful Mw 7.1 quake struck the same region. Because the Mw 7.1 earthquake is the largest event so far in this sequence, it is considered to be the mainshock. The events leading up to it, which include the Mw 6.4 quake, are considered to be foreshocks.

From this sequence of earthquakes, it is clear that the Mw 6.4 foreshock had triggered seismicity on conjugate faults (i.e. intersecting faults that criss-cross in a X-shape) along the Eastern California Shear Zone which runs somewhat parallel to the San Andreas Fault, but is...