KUALA LUMPUR: Some of the 750 active volcanoes in Southeast Asia can affect Malaysia if they erupt.
A volcanologist at Universiti Kebangsaan Malaysia's Department of Earth Sciences and Environment said this could happen despite the fact that Malaysia is located outside the Pacific Ring of Fire.
Dr Suraya Hilmi Hazim said there are about 750 volcanoes across the region that are classified as active or potentially active.
Eruptions could affect economic, health and environmental aspects, she said.
"The ones with direct impact will be those closest to us, but the intensity of the impact will depend on the size of the eruption and the type of volcano.
"For example, with (Indonesia's) Gunung Ruang, we had numerous flight cancellations due to the presence of volcanic ash in our airspace."
Suraya said this could affect the country's economy, depending on how long the airspace is closed.
"In terms of the environment and health, it will probably be similar to the effects of the transboundary haze. Respiratory systems will be affected and water will be contaminated, but this will take a significantly large eruption with plenty of ash.
"This ash is not like normal ash. It is microscopic silica and broken pieces of rocks that can clog engines, waterways and living organisms' airways."
Suraya said geologists cannot predict an eruption.
"Volcanoes are extremely complex systems that do not follow a predictable schedule. No two volcanoes are the same. Even the ones which have the same shapes and the same composition of magma rarely erupt in the same patterns."
However, geologists employ several ways to assess the level of activity in a volcanic region.
These include using seismometers, tiltmeters and satellite imagery, she said.
She said regular data collection is crucial to detect anomalous activity in a volcanic region.
"While geologists cannot predict eruptions with certainty, having monitoring-based forecasts, while imperfect, aids in better risk mitigation."
