LETTER | Unlike Indonesia, Japan and the Philippines, Malaysia is not situated directly on a major active plate boundary. Hence, Malaysia is generally regarded as a country with relatively low earthquake risk.

The tremors occasionally felt in Peninsular Malaysia are usually associated with earthquakes originating in neighbouring Sumatra. Consequently, earthquakes have traditionally received relatively little attention in industrial risk assessments in Malaysia.

Recent events in Johor may justify a rethink.

In recent months, several small earthquakes were detected around Batu Pahat and other parts of Johor. These earthquakes were of low magnitude and only caused little or no damage. There is certainly no reason to create a public alarm.

Nevertheless, their recurrence raises an important question: should seismic hazards now receive greater consideration in the risk assessments of major industrial installations?

I was involved in industrial risk assessment of major process installations in southern Johor about 10 years ago. At the time, earthquakes were not considered a significant initiating hazard because Malaysia had no history of significant earthquakes.

Given the knowledge and experience available then, this was understandable.

But risk assessment should never be regarded as a once-and-for-all exercise.

When new information becomes available, the assumptions underlying an assessment should be reviewed.

Challenging assumptions

Recent geological findings indicate that some of the earthquakes in Johor may be associated with movement or reactivation of ancient geological faults.

This does not mean Johor is becoming an earthquake-prone region or that a major earthquake is imminent.

It does, however, challenge the assumption that the absence of significant historical earthquakes means there is no local seismic hazard.

This distinction is particularly important for major industrial installations handling flammable, toxic or otherwise hazardous materials.

For an ordinary house, a small earthquake may be little more than an unsettling experience. At a major industrial facility, however, the concern is not necessarily the earthquake itself, but what could happen as a consequence.

Seismic movement could potentially affect piping, storage tanks, electrical equipment, instrumentation, utilities or fire-protection systems. Damage to a relatively small component could result in loss of containment and, depending on the material involved, potentially lead to fire, explosion or toxic release.

More concerns

There is another concern. Industrial safety systems are often designed around individual equipment failures. An earthquake, however, can affect several systems at approximately the same time.

Electricity may be disrupted while instrumentation is affected. Access to certain areas may become difficult while fire-water systems or other utilities are also compromised.

Such scenarios deserve consideration in the emergency planning of major-hazard installations.

This does not mean every factory in Malaysia needs to be redesigned to withstand a major earthquake. Nor should the recent tremors automatically lead to costly new requirements for industry.

A sensible first step would be seismic screening.

Consider seismic hazards

For existing major-hazard installations, operators and regulators could consider whether the location is near known or suspected fault systems and whether earthquakes should be included as an initiating event in the facility's hazard identification and emergency-response planning.

For new major industrial projects, seismic hazards could similarly be considered during the early stages of design and risk assessment rather than being dismissed because significant earthquakes have historically been uncommon.

Malaysia is already strengthening its seismic monitoring and improving its understanding of geological faults. This is welcome.

The same principle should apply to industrial safety: risk assessments should evolve when our understanding of hazards evolves.

The recent tremors in Johor may ultimately prove to be nothing more than minor geological adjustments. But they provide a timely opportunity to revisit a long-standing assumption.

The objective is not to create fear or impose unnecessary costs on industry. It is simply to ensure that major industrial installations are assessed against the best information available.

When our understanding of the hazard changes, should our risk assessments change with it?

The views expressed here are those of the author/contributor and do not necessarily represent the views of Malaysiakini.