Indonesia earthquake triggers tsunami warning for coastal zones

Indonesia sits on the Pacific Ring of Fire, a belt of tectonic activity that produces regular earthquakes and eruptions. A magnitude 7.5 quake and tsunami in 2018 killed more than 4,000 people on Sulawesi island.

Tsunami warnings from national agencies typically last two to three hours, after which BMKG reassesses based on tide gauge readings. The agency said it would update its warning as data arrives.

Geological history alone does not determine the course of a specific event. Each quake produces a different wave pattern. The real factor is whether the rupture displaces enough seafloor vertically to move water. The USGS said the region's tectonic setting, where the Australian plate slides under the Pacific plate, makes vertical displacement more likely in some segments than others.

For residents in the warning zone, the immediate focus is distance from shore. BMKG urged those near beaches in North Maluku and North Sulawesi to be cautious until the all-clear.