Earth Observatory Blog

Submitted on 15 Jan 2021 by:

A moderate earthquake struck western Sulawesi, Indonesia, on 15 January 2021 at approximately 2:28am (SGT). According to the United States Geological Survey, the Mw 6.2 event occurred about 36 kilometres (km) south of Mamuju on the island of Sulawesi at a depth of 18 km.

This event follows a smaller Mw 5.7 foreshock event that occurred approximately 12 hours earlier at about the same location.

Today’s event is due to compressional forces on a fault system that has left a visible record in the topography and geology. However, not many earthquakes have happened on this fault system in the recent past. “The east-dipping thrust fault here is part of an obscure system of faults that extends offshore and is not well studied,” said Dr Kyle Bradley, a Principal...

Submitted on 29 Dec 2020 by:

Dear EOS Community,

This year has been an extraordinary one and has been challenging for many, but it has demonstrated how resilient and innovative we can be in response to unique circumstances during this “new normal”. We continued addressing critical questions in Earth science, conducted more research in Singapore than ever before, and brought our science to the public with two exhibitions and a documentary series in collaboration with our partners.

EOS Leadership Transition

I am indebted to Director Emeritus Kerry Sieh for founding EOS and for inviting me to be part of the team in Singapore three years ago. Kerry’s legacy is a world-class research institute, dedicated to...

Submitted on 28 Dec 2020 by:

A rock collection might not seem exciting at first sight. But do you know that the collection from the newly opened Geology Gallery at the Sentosa Nature Discovery, reveals Singapore’s geological past?

Here is an interesting fact: Singapore’s geological past was not always as quiet as it is now. The rocks on display at the Gallery provide clues to each environment Singapore once experienced. By gathering these clues, scientists can put together a narrative of our small island-state’s geological history spanning hundreds of millions of years.

300 million years ago, Singapore and Kuala Lumpur were located thousands of kilometres away from each other. Today, this distance has shortened to approximately 355 kilometres. This phenomenon can be explained by the movement...

Submitted on 21 Dec 2020 by:

In conversation with Dr Karen Lythgoe, Research Fellow at the Earth Observatory of Singapore


1. What area of earth science do you study and monitor?

I am a seismologist at the Earth Observatory of Singapore at Nanyang Technological University, where I monitor and study earthquake hazards and sub-surface imaging both for the deep and the shallow earth. I apply seismology to important Earth science problems, including earthquake processes, Earth structure and dynamics, and smart city development.

2. What opportunities exist to capture heat from the deep earth to create low carbon energy and reduce the emission of greenhouse gases?

Recently there was ...

Submitted on 01 Dec 2020 by:

The activity of Ili Lewotolok (or Lewotolo) volcano ramped up on 29 November 2020 with a series of eruptions. The largest of these eruptions occurred at about 9:45am local/Singapore time (1:45am UTC) and sent a gas and ash plume more than 5 kilometres (km) into the atmosphere. This powerful eruption was recorded by the infrasound network from the Earth Observatory of Singapore (EOS).

Scientists from EOS use infrasound sensors to remotely characterise volcanic eruptions. Even if Ili Lewotolok volcano is about 2,500 km away from Singapore, the eruption on 29 November produced a clear infrasound signal on the Singapore Infrasound Array. The same...

Submitted on 19 Nov 2020 by:

Typhoon Goni (Rolly in the Philippines) caused more than 20 fatalities in the Philippines earlier this month. Just a few days later, Typhoon Vamco (Ulysses) struck the Philippines again, then Vietnam on the other side of the South China Sea. “It is fairly common for more than one storm to occur in an ocean basin at the same time”, said Associate Professor Adam Switzer, a Principal Investigator at the Earth Observatory of Singapore. “Since typhoon season in Asia runs into the new year, there is unfortunately a real chance of further storms in the region before the end of 2020”, Assoc Prof Switzer added.

Typhoons form under specific sets of conditions between the ocean and the atmosphere. For example, warm sea...

Submitted on 23 Sep 2020 by:

In conversation with Fangyi Tan, PhD student, Sea Level Research team at the Earth Observatory of Singapore


1. Will melting ice sheets in such quantities pose a threat to Southeast Asia in the future? 

recent study found that the Earth has lost a staggering 28 trillion tonnes of ice between 1994 and 2017. The scientists commented in a related news article that the melting of glaciers and ice sheets could cause sea levels to rise by as much as a metre by the end of this century.

One metre may not sound like a lot...

Submitted on 15 Sep 2020 by:

When a volcano erupts in the darkness of night, or when it is blanketed by clouds, determining even the most basic information about the plume can be very difficult. Particularly for air safety, information like the time the eruption started, the height of the plume, and the eruption duration are crucial for determining what air spaces will be impacted.

Published on 15 September 2020, in the Journal of Volcanology and Geothermal Research, is a study I led that developed a new method to estimate plume heights. This method utilises the long-travelling low-frequency sound waves produced by the eruptions.

Infrasound, or sound that falls below 20 Hz, can travel thousands of kilometers and...

Submitted on 06 Aug 2020 by:

In conversation with Assistant Professor Aron Meltzner, Principal Investigator at the Earth Observatory of Singapore


1. How does the recent powerful magnitude-7.8 earthquake in Alaska remind us of similar hazards in Southeast Asia?

Last week, we saw a powerful earthquake off the coast of Alaska with a magnitude of 7.8 which had the potential to trigger a damaging tsunami, but fortunately this did not happen.

It occurred along a subduction zone where the Pacific Plate is subducting or slipping under the North American plate. The shaking that we know as an earthquake results from the sudden movement between these two plates, but that sudden movement also has the potential to lift up the seafloor, which in turns lifts the water above it, and that can...

Submitted on 21 May 2020 by:

Did you know that in the past six weeks six volcanoes in Indonesia erupted? These volcanoes are Semeru, Anak Krakatau, Merapi, Kerinci, Dukono, and Ibu. 

These recent eruptions are part of the usual volcanic bustle in Indonesia, impacting mostly the areas close to the volcanoes. While some of these activities were picked up all the way in Singapore, all were reported to aviation authorities.

Issuing Eruption Notifications

The Centre for Volcanology and Geological Hazards Mitigation (CVGHM), the monitoring agency for Indonesian volcanoes, issued a Volcano Observatory Notification for Aviation (VONA) on each eruption. The notification includes a summary of the volcanic activity, the...