PUTRAJAYA, Aug 28 — The magnitude 3.2 tremor that struck Segamat, Johor, yesterday was caused by the reactivation of the Mersing Fault due to regional tectonic stress, said the Department of Minerals and Geoscience Malaysia (JMG).
It noted that Malaysia lies on the relatively stable Sunda Plate but remains influenced by regional forces, particularly from the Sunda subduction zone off western Sumatra.
These pressures can reactivate existing faults in Peninsular Malaysia, triggering small to moderate earthquakes.
“Preliminary mapping placed the Segamat epicentre near the extension of the Mersing Fault, which trends west-northwest to east-southeast.
“Seismological analysis indicated a left-lateral strike-slip movement, with the northern block shifting west and the southern block moving east,” JMG said in a statement today.
The shallow depth of approximately 10 km confirmed that the tremor was caused by continental crust movement, rather than volcanic activity or deep-sea subduction.
Peninsular Malaysia has previously recorded tremors in Bukit Tinggi (Pahang), Kenyir (Terengganu), Kuala Pilah (Negeri Sembilan) and Manjung–Temenggor (Perak). Johor also experienced minor earthquakes in 2021 and 2023, linked to seismic activity off the coast of Sumatra.
“These incidents, including the Segamat quake, show that the continental plate beneath Peninsular Malaysia still stores tectonic stress that may be released periodically,” it said.
As such, JMG emphasised the need for continuous monitoring, updated fault mapping, and early warning systems to enhance preparedness and protect infrastructure.
Together with the Malaysian Meteorological Department under the Natural Resources and Environment Sustainability Ministry (NRES), JMG will step up monitoring and scientific analysis in at-risk areas, whether due to local or regional seismic activity.
