BMKG: 7.7 Magnitude Earthquake in Celebes Sea is Not from Megathrust Zone

The Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG) is confident that the series of tectonic earthquakes with a magnitude of 7.7 in the Celebes Sea, which were followed by micro-scale tsunamis, were triggered by the subduction activity of the Philippine Sea Plate and did not originate from a megathrust zone.

During a press conference in Jakarta on Monday, the Director of Earthquakes and Tsunamis at BMKG, Wijayanto, explained that based on data analysis from the National Earthquake Centre, the characteristics of the earthquake source are located within the active subduction zone of the Philippine Sea.

Although the source is a non-megathrust subduction zone, BMKG stated that the significant magnitude of the earthquake still caused underwater rock deformation, which has the potential to trigger tsunamis. As of 08:20 WIB, monitoring stations recorded tsunami heights ranging from 9 to 75 centimetres in several areas, including Tanjung Sidupa Village in North Bolmong and Talengen Village in the Sangihe Islands.

Wijayanto reminded the public that these initial detections represent only the first wave phase, and strict monitoring is ongoing. “We will continue to monitor, as this is still the first wave. We will certainly continue to update journalists if any further activity is recorded in other locations,” he said.

In addition to the tsunami potential being monitored, the BMKG Earthquake Centre had recorded at least five aftershocks as of 07:40 WIB. BMKG confirmed that the magnitude trend of these five aftershocks has shown a significant decrease compared to the main earthquake that occurred at 06:37 WIB.

Consequently, the agency urged residents in the northern and eastern coastal regions of Indonesia not to speculate on megathrust earthquake issues that do not align with scientific data, and to strictly follow official BMKG evacuation instructions until the tsunami early warning status is officially lifted.