Including One Of The Sources Of The Earthquake In Madura, What Is The RMKS Fault Zone?

Illustration (PIxabay)

YOGYAKARTA The tectonic earthquake with a magnitude of 6.5 that rocked the Sumenep region in Madura on Tuesday, September 30, 2025 night, was triggered by active fault activity under the sea. This phenomenon again reminds the existence of the RMKS Fault Zone which was once the cause of the destructive earthquake in the region. So, what is the RMKS Fault Zone? To find out, see the explanation in the following article.

Please note, Madura Island in East Java is one of the areas prone to natural disasters in earthquakes. Although the record for seismic activity in the region is relatively low (low seismicity), geological facts show that Madura is on an active fault path called the RMKS Fault Zone.

Compiled from various sources, which is referred to as the RMKS (RMKS Fault Zone) fault zone, is a large fault line that stretches from Rambang in Central Java, passes through Madura, Kangean, to Sakala in the eastern Java Sea.

The fault zone itself is a zone for fracture or fracture of rocks in the earth's crust. Meanwhile, RMKS is an acronym for Rembang, Madura, Kangean, and Sakala.

The RMKS fault stretches towards the East and is north of the Flores Fault.

Geologically, this fault zone is horizontal and wide enough, stretching from the north of East Java to cutting Madura Island, to Sakala in northern Kangean.

The RMKS fault zone length reaches more than 300 kilometers and is estimated to have formed since more than five million years ago.

The Kambing Fault, which is part of the RMKS Fault Zone, is located on the seabed and stretches through Kambing Island.

Menukil laman resmi BMKG, Sesar RMKS pernah menjadi penyebab gempa bumi merusak di Rembang-Tuban pada 1836, Sedayu (1902), Lamongan (1939), Sumenep (13 Juni 2018 dan 11 Oktober 2018).

Reports of seismic activity in this region are proof that RMKS is an active fault path that can trigger significant earthquakes in East Java and its surroundings.

Based on research published in the journal Geoscience and Technology in 2024, the RMKS Fault, which is mostly located on Madura Island, has a very interesting geological structure. This is because the fractures on the island are influenced by the interaction of two large tectonic plates, namely Indo-Australia and Eurasia. This interaction is the cause of the formation of faults or faults in the earth's crust.

Referring to a report from the National Earthquake Study Center, the RMKS Fault includes a shear fault for mengiri (sinistral strike slip) located in the Java Sea, precisely in the north of Madura Island and south of Bawean Island with a length of 1200 km, a Southeast strike and a 90 degree dip.

The RMKS fault zone has a west-east direction, forming a deformation zone with a width of about 15 to 40 kilometers with a length of 675 kilometers. This fault is classified as active and can trigger a destructive earthquake natural disaster.

That's the information about what the RMKS Fault Zone is. Get news updates of other options only on VOI.ID.