TEMPO.CO, Jakarta - A total of 105 tectonic earthquake incidents occurred in West Java, Indonesia, throughout August 2025. Although not all of them were felt by the public, the number recorded by the Meteorology, Climatology, and Geophysics Agency (BMKG) has significantly increased compared to the 71 earthquakes in the previous month.
The head of the BMKG Geophysics Station in Bandung, Teguh Rahayu, stated that 96 out of the 105 earthquake events in West Java were classified as shallow, occurring at a depth of less than 60 kilometers. There were also 8 medium-category earthquakes at depths ranging from 60-300 kilometers, and one earthquake with a deeper epicenter.
"In terms of magnitude, the largest recorded earthquake was 4.9 and the smallest was 1.3," he told Tempo on Monday, September 1, 2025.
A total of 54 earthquake events in West Java throughout August 2025 originated from the sea, while the rest occurred on land. According to Rahayu, 12 tremors were directly felt by the public. He stated that compared to July, the tremors felt by residents were twice as strong.
One significant incident recorded by the BMKG in West Java was a 4.7 magnitude earthquake in South Karawang on Saturday night, August 20, 2025. The tremors from a depth of 10 kilometers were felt in Bekasi, Purwakarta, Cikarang, Depok, Bandung, Jakarta, Tangerang Selatan, Bekasi Timur, Tangerang, Pandeglang, Cianjur, Lebak, and Pelabuhan Ratu.
The M4.7 tremor was triggered by the activities of the West Java Back-arc Thrust. This fault has been active since five million years ago, and the recent earthquake came from its segment known as the Citarum Segment.
Researcher at the Geological Disaster Research Center of the National Research and Innovation Agency (BRIN), Sonny Aribowo, mentioned that this earthquake fault has been active since the Pliocene era around 5 million years ago," he said when contacted on August 25, 2025.
This damaging earthquake is part of a long series of aftershocks. By the end of the month, there had been 22 aftershocks following the 4.7 magnitude tremor in Karawang. Only four out of the total earthquakes were felt by the public.
Two active segments on the western side of the Lembang Fault, namely Cimeta and Cipogor, also caused earthquakes with magnitudes ranging from M1.7 to M2.3. The strongest tremor scale could reach III MMI.
Faiz Zaki contributed to the writing of this article.