Earth Observatory Blog

Submitted on 09 Mar 2020 by:

113 years ago, on 4 January 1907, a powerful magnitude (M) 8.2-8.4 earthquake occurred off the west coast of Sumatra, Indonesia. This earthquake belonged to a special class called “tsunami earthquakes” that do not generate very strong shaking, but can result in large tsunamis.

The tsunami that was produced struck Nias and Simeulue, killing thousands. It also struck the distant shores of Sri Lanka, India, and the island of Reunion. The first earthquake was later followed by another quake measuring approximately M 7.0, resulting in the destruction of countless houses.

In the years that followed, the sequence got jumbled and the two events were conflated as one, but the 1907 disaster was preserved in local memory by way of the legend of the Smong – a Devayan word for...

Submitted on 27 Feb 2020 by:

At the 13th International Conference on Paleoceanography held on the 2nd to 6th September 2019 in Sydney, Australia, Dr Yama Dixit, a Research Fellow at the Earth Observatory of Singapore (EOS), gave a talk on the historical variations of the Indian Summer Monsoon (ISM) that she had discovered were recorded in the shells of freshwater snails found in the lakes of India.

When the world’s climate changes in significant or unexpected ways, these anomalies impact different regions in a dissimilar manner. During the last Little Ice Age between 1500 and 1850 AD, for...

Submitted on 19 Feb 2020 by:

In the early morning at about 5am on 12 February 2020, a bright object was seen in the sky. It blazed over Singapore and Johor Bahru, Malaysia, and its lights were caught on two dash-cam videos. The video that was filmed in Singapore was captured near the Nanyang Technological University campus, next to the Jalan Bahar flyover.

When an object enters the Earth’s atmosphere and burns up on entry, the way we name it depends on how big it is, as well as how bright. For example, an asteroid is a piece of rocky, iron, or icy debris, over...

Submitted on 02 Dec 2019 by:

I was part of a team who recently went to Myanmar to repair instruments that are key to understanding natural hazards in the region. We worked and stayed with the locals the whole time, which was an amazing way to discover the Myanmar culture.

Myanmar lies in the complex boundary zone on the eastern edge of the Indian plate. It is therefore prone to seismic hazards. However, due to political leadership, little was known about these hazards until 2010 when the first research projects got started. 

Between 2011 to 2017, 17 GPS stations, 30 Seismic stations, and 10 strong motion accelerographs (SMA) were installed by the Centre of Geohazard Observations (CGO) at the Earth Observatory of Singapore, in collaboration with the Myanmar Earthquake Committee, and...

Submitted on 25 Nov 2019 by:

Singapore, unlike Japan, does not have any volcanoes. However, our little sunny island is in proximity to 127 active volcanoes in Indonesia and 53 in the Philippines. This means that like Japan, Singapore too could be significantly affected by different types of volcanic hazards, making research on volcanoes an important area of study for both countries. Here’s how Singapore was once affected.

Singapore was impacted by volcanic ash in 1991 after the eruption of Mount Pinatubo in the Philippines. And with that many volcanoes around the country, it is unlikely to be a one-off. As for Japan, it is in constant alert with its currently 110 active volcanoes. But, despite a very developed monitoring system, some eruptions – such as the 2014 Ontake eruption – still have...

Submitted on 30 Sep 2019 by:

Just after 6pm on 28 September 2018 (Singapore time), a magnitude-7.5 earthquake struck central Sulawesi. The powerful quake generated a tsunami which, along with massive landslides, devastated Palu and the town of Donggala. These resulted in more than 4,000 people dead or missing.

In an economic loss assessment report issued by Indonesia's National Disaster Management Agency (BNPB), the Palu earthquake event caused more than S$1.5 million in damages.

Today, a year later, scientists from the Earth Observatory of Singapore (EOS) and their teams are ready to share some of their findings about this earthquake-tsunami event.

A Complex Rupture Sequence

Using a combination of seismic, geodetic, geologic, and written records, Assistant Professor Wei...

Submitted on 28 Sep 2019 by:

During the early evening of 28 September 2018, a magnitude-7.5 earthquake struck along the coast of northwestern Sulawesi, Indonesia. This region hosts a famous strike-slip fault system called the Palu-Koro Fault.

Even though this is one of the fastest slipping faults in the world, it has not produced many large earthquakes during historical times. The Palu-Koro Fault was therefore thought to have a high probability of a large and destructive earthquake, and so the occurrence of the 2018 quake in Sulawesi wasn’t very surprising.

However, the landsliding that was triggered by the earthquake turned out to be unexpectedly destructive. Soon after the earthquake, witnesses described entire villages south of Palu City sinking into mud and disappearing, and it was...

Submitted on 20 Sep 2019 by:

At home and abroad there is increasing agreement that we are facing an existential environmental crisis. Death, destruction, and disruption by extreme weather events, haze from forest fires, and contamination of oceans by plastic waste have dramatically increased the awareness of environmental degradation, and given rise to a realisation that the conclusions from decades of scientific research, and the dire predictions arising from it, indeed point to a considerable challenge to society.  

Singapore’s Prime Minister Lee Hsien Loong said in the 2019 National Day Rally speech that “climate change is one of the gravest challenges the human race faces and Singapore is already feeling its impact – which is likely to worsen over the next few decades”. 

Last week...

Submitted on 09 Jul 2019 by:

 

On 5 July 2019 at 1.33am (Singapore time), a Mw 6.4 earthquake struck the town of Ridgecrest in California. Its seismic waves could be felt from Los Angeles to San Jose. Nearly a day and a half later, on 6 July at 11.19am (Singapore time), a more powerful Mw 7.1 quake struck the same region. Because the Mw 7.1 earthquake is the largest event so far in this sequence, it is considered to be the mainshock. The events leading up to it, which include the Mw 6.4 quake, are considered to be foreshocks.

From this sequence of earthquakes, it is clear that the Mw 6.4 foreshock had triggered seismicity on conjugate faults (i.e. intersecting faults that criss-cross in a X-shape) along the Eastern California Shear Zone which runs somewhat parallel to the San Andreas Fault, but is...

Submitted on 20 Mar 2019 by:

What lies beneath Singapore?

With land in scarce supply, Singapore is increasingly looking underground for storage spaces and even city construction. A team from the Earth Observatory of Singapore (EOS) have started working on a seismic survey to find out more about Singapore’s underground seismic structure and seismic hazard. A total of 88 seismometers have been deployed at 87 sites across Singapore, including school, parks, nature reserves, and weather stations.

The underground may also hold valuable resources for Singapore, such as water and energy. One example of this is geothermal energy. Hot springs in Singapore are generated by hot rocks deep underground. We want to identify the source of this...

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