Malaysia maps 11 active earthquake fault zones, moves to speed up quake alerts

Mapping the fault lines across Malaysia

Malaysia has formally mapped 11 active earthquake fault zones across the country, an effort that brings new clarity to where ground movement is possible and how engineers and planners should respond. Plantation and Commodities Minister Johari Abdul Ghani said the Minerals and Geoscience Department completed nationwide fault mapping between 2016 and 2020, and the findings are now informing building standards, infrastructure planning, and emergency preparedness.

Six active faults have been identified in Peninsular Malaysia: Bukit Tinggi in Pahang, Bokbak spanning Kedah and Perak, Terengganu in Terengganu, Banding in Perak, Kuala Pilah in Negeri Sembilan, and Mersing in Johor. In East Malaysia, Sarawak has the Tubau Fault in Miri, while Sabah hosts four, Lobou Lobou and Mensaban in Ranau, and Lahad Datu and Tabin in the Lahad Datu area.

To track subtle ground movement, authorities have installed six active fault movement benchmark stations in Sabah and operate 47 passive stations across Pahang, Selangor, Perak, Negeri Sembilan, Sarawak, and Sabah. Plans are underway to extend both mapping and benchmark coverage to other higher risk districts, including parts of Johor.

These maps and instruments are the backbone of a wider strategy that includes updated hazard models, faster alerts, and guidance for engineers to follow the Malaysia National Annex to Eurocode 8, the standard used to design structures for earthquake resistance.

What does it mean when a fault is active?

An active fault is a fracture in the Earth’s crust where movement has occurred in recent geological time and could occur again. In Malaysia, activity can show up as micro tremors that are too small to be felt or as shallow earthquakes that some communities notice. Mapping these structures helps estimate how strong shaking could be in nearby towns and how often it might occur.

Why Malaysia experiences quakes despite being outside the Ring of Fire

Peninsular Malaysia sits on a relatively stable portion of the Eurasian Plate, yet it still feels shaking. The main reason is proximity to Sumatra, where the Sunda megathrust and the Sumatran fault zone generate large earthquakes. Energy from those events travels across the Strait of Malacca and can cause light to moderate shaking in western and central parts of the peninsula. Local intraplate faults, including some of those now mapped, also release stress from time to time.

Peer reviewed studies that used both deterministic and probabilistic hazard methods show that cities between roughly two and four degrees north latitude, including the Klang Valley corridor, experience higher peak ground acceleration values than other parts of the peninsula, primarily due to nearby Sumatran sources. Researchers have also demonstrated that local faults add to this risk, even if they produce smaller events, because of their proximity to towns and infrastructure.

Reservoir induced earthquakes have been recorded near major dams such as Kenyir and Temenggor. These usually involve small to moderate tremors triggered by changes in water pressure within rock layers, which can alter stress conditions along preexisting faults.

Six states flagged for elevated seismic risk

Officials have identified six states with mapped fault zones and higher exposure to seismic hazards: Pahang, Terengganu, Perak, Negeri Sembilan, Sabah, and Sarawak. This does not mean large earthquakes are expected in these states. It signals that local authorities should apply modern design standards and strengthen monitoring in places where faults and population centers intersect.

The recent cluster of minor quakes in Johor, including tremors felt around Segamat and Batu Pahat in late August and September, drew attention to the Mersing Fault Zone that runs through eastern Johor. Recorded magnitudes ranged roughly from 2.5 to 4.1 and were shallow. Engineers describe these as part of a natural release of tectonic energy along older fault structures.

Based on current data, the expected intensity in areas such as Segamat and Batu Pahat is moderate at most. Authorities say routine monitoring and the application of appropriate building standards remain the focus.

How hazard maps guide safer buildings

Seismic hazard maps translate science into numbers that engineers can use. The maps estimate the shaking a site might experience over a given timeframe, usually expressed as peak ground acceleration (PGA) for return periods such as 475 years and 2475 years. Local authorities use these values to set requirements for new construction and to prioritize retrofits.

Malaysia’s design practice references the Malaysia National Annex to Eurocode 8. It provides guidance on structural systems, ductility, detailing, and site classification so that buildings can withstand the level of shaking anticipated for their location.

Recent academic work that incorporates both distant Sumatran sources and local faults estimates PGA on rock sites across Peninsular Malaysia in the range of about 1 to 10 percent g for the 475 year level and about 2 to 20 percent g for the 2475 year level. Values vary across districts, which is why planners rely on hazard maps rather than a single national number.

For complex urban areas, experts recommend microzonation, a finer scale mapping of soil conditions and fault proximity. This approach can highlight neighborhoods with softer soils that may increase shaking and can inform site specific design checks for essential facilities such as hospitals, schools, and bridges.

Monitoring network and faster alerts

Malaysia’s Meteorological Department (MetMalaysia) operates 80 seismographic stations at strategic locations nationwide, supported by real time feeds from 323 international stations. The system issues alerts within about eight minutes for earthquakes of magnitude 3.0 or larger that occur in or near Malaysia. Under the current national plan, upgrades aim to reduce this alert time to about six minutes by 2026.

As part of a wider enhancement program, 12 seismic monitoring stations are being strengthened. In Johor, two new stations are planned in Segamat and Muar, and four existing stations in Johor Bahru, Batu Pahat, and Gelang Patah are being upgraded to better detect low magnitude local quakes. Data transmission uses satellite links to ensure continuity during storms or power disruptions.

Earthquakes cannot be predicted. After undersea earthquakes, however, tsunamis can be detected and tracked. That is why early warning investments prioritize both seismic detection and sea level monitoring, along with clear procedures for disseminating alerts to authorities and the public.

What faster alerts change

Faster alerts help responders put lifeline services on standby, temporarily halt rail lines for inspections, and issue guidance to schools and hospitals. For events that are felt but not damaging, quick authoritative information also calms rumor and reduces unnecessary evacuations.

Sabah and Sarawak: unique challenges

Sabah has four mapped active faults in Ranau and Lahad Datu, and the state has experienced damaging earthquakes in living memory, including a 2015 event near Ranau that triggered rockfalls on Mount Kinabalu. The landscape is steep and much of the housing stock includes lightweight construction, which changes how structures respond to shaking.

Sarawak’s Tubau Fault near Miri is the main mapped structure in the state. Both Borneo states are covered by an expanding network of benchmark stations that track slow ground movement. In Sabah, six active movement benchmark stations support close surveillance of deformation across the fault systems.

Local governments in East Malaysia increasingly reference hazard information for land use and site selection, avoiding known fault traces for critical facilities and lifting construction standards where needed.

What engineers and local authorities should do now

Apply the Malaysia National Annex to Eurocode 8 consistently for public buildings, high occupancy structures, and essential infrastructure. Site class matters, so require proper geotechnical investigations on new projects and, where practical, site specific response spectra for hospitals, emergency centers, and major bridges.

Conduct screening level assessments of older buildings in towns close to mapped faults, focusing on soft story configurations, unreinforced masonry, nonductile concrete frames, and heavy nonstructural components such as parapets or unbraced partitions. Simple fixes such as bracing water tanks and securing equipment can reduce risk.

Expand microzonation in urban areas that sit within the higher PGA corridor, including the Klang Valley, Seremban, Melaka, Ipoh, Penang, Johor Bahru, and growing towns in Johor such as Segamat and Kluang. Feed results into planning approvals and emergency response plans.

Strengthen lifeline resilience. Prioritize seismic checks for power substations, water treatment plants, pipelines, elevated tanks, telecom hubs, and transport viaducts. Where weaknesses are found, phase in retrofit programs that target the most cost effective measures first.

Maintain public education programs that explain what to do during shaking, how to prepare at home and at work, and how official alerts are delivered. Familiarity with procedures leads to faster, calmer response when events occur.

Voices from the field

Seismic engineering expert Dr Azlan Adnan urged vigilance, updated hazard maps, and more detailed studies in urban centers that sit near mapped faults or within corridors exposed to Sumatran sources.

The country lies near a major seismic zone in Sumatra and also has legacy fault lines within the peninsula which can occasionally reactivate.

It is a time to be vigilant, not to panic.

Government officials say the national hazard map is being refreshed and that seismic and tsunami services are being enhanced under the current development plan. The goal is faster detection, richer data for engineers, and steady improvements in standards as new geological information becomes available.

Key Points

• Malaysia has mapped 11 active fault zones, six in Peninsular Malaysia and five in East Malaysia.
• Peninsular faults are Bukit Tinggi, Bokbak, Terengganu, Banding, Kuala Pilah, and Mersing.
• East Malaysia includes the Tubau Fault in Sarawak and four faults in Sabah, Lobou Lobou, Mensaban, Lahad Datu, and Tabin.
• Six states are flagged for higher exposure to seismic hazards: Pahang, Terengganu, Perak, Negeri Sembilan, Sabah, and Sarawak.
• MetMalaysia runs 80 seismographic stations, with data from 323 international stations, issuing alerts in about eight minutes and targeting six minutes by 2026.
• Upgrades include strengthening 12 seismic stations, adding two new stations in Segamat and Muar, and improving four stations in Johor for better detection of small local quakes.
• Engineers are guided by the Malaysia National Annex to Eurocode 8, with hazard maps that incorporate both Sumatran and local faults.
• Earthquakes cannot be predicted, while tsunamis can be detected after undersea quakes, making rapid alerts and public readiness essential.