Earth Observatory Blog

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

Usinga combination of seismic, geodetic, geologic, and written records, Assistant Professor Wei Shengji...

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 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 27 Jun 2019 by:

Social media has found itself a heavyweight role in geology. By scraping Twitter and mining text data in Tweets, scientists at the Nanyang Technological University can now track where volcanic ash has fallen. This breakthrough won Assistant Professor Benoit Taisne and Professor Gao Cong the Accelerating Creativity and Excellence (ACE) Award for their research project titled “Detecting and Tracking Volcanic Ash Using Social Media Data”.

Asst. Prof Taisne, a principal investigator at the Earth Observatory of Singapore (EOS), worked closely with...

Submitted on 30 May 2019 by:

I went to Banda Aceh, Indonesia in 2006 to help assess the impact of the 2004 Indian Ocean tsunami upon the region’s rich cultural heritage. The scale of destruction caused by the tsunami was staggering. Half the city had been pulverised and all that was left was a mix of concrete, broken furniture, household items, and a colorful patchwork of shreds of clothing. We found clusters of beautifully carved stone grave markers dating back centuries amongst the rubble, half buried in mud and debris, or piled up neglected near areas being cleared by NGOs and donors for new tracts of post-disaster housing.

The same waves that killed over 150,000 people and displaced millions had reached back into the past and threatened to wipe out the historical memories of Aceh’s coastal...

Submitted on 24 Apr 2019 by:

When the time came for us to choose a place to house the EOS Dynamic Earth Games, the answer was a clear and obvious one – the Science Centre Singapore (SCS).

SCS has an impressive 40-year record of making science fun and accessible to the public. They successfully reach out to and engage more than one million visitors annually.

We, at the Earth Observatory of Singapore (EOS), know just how capable the SCS team is. We have worked with them over the years on various projects and launches (e.g. “Earth: Our Untamed Planet” exhibit currently in SCS, and the film screening of EOS documentary The Ratu River). Most recently, we spent the past six months working closely with SCS and acclaimed Californian science museum, The Exploratorium, on a new earth science exhibition...

Submitted on 10 Apr 2019 by:

Did my last blog post about the Dynamic Earth Games (DEG) leave you hungry for more details about the games? Well, I hope to satisfy your curiosity in this second post.

The Earth Observatory of Singapore (EOS) collaborated with BOHO Interactive and the Science Centre Singapore to develop seven different games. These fall into three broad categories:

Volcanoes and Typhoons, Assessing Risk, and Evacuation.

Volcanoes and Typhoons

The Dynamic Earth Games explain the science behind natural hazards with a strong focus on geology and meteorology. While playing the games, you will learn some of the signs of an impending volcanic eruption and the tools that...

Submitted on 03 Apr 2019 by:

What makes up the exciting memories of my first interaction with science? I recall touching the slimy texture of snails, sniffing ammonia salt (also known as “smelly salt”), and making my sister’s hair stand with a balloon.

For me, science is a journey – a fun-filled adventure that satisfies our curiosity of the universe. Think about it. What makes us enjoy playing soccer, chess, or Candy Crush? Games are fun because they involve elements of competition with others, even ourselves, and some require us to cooperate with one or more people. This sense of competition and camaraderie are essentially what makes us enjoy playing games.

The Dynamic Earth Games, an Earth Observatory of Singapore (EOS) series of board games and card games about natural hazards, use these...

Submitted on 18 Feb 2019 by:

On 29 July 2018, Lombok was struck by a 6.4-magnitude earthquake, killing 20 people. A week later, an even stronger earthquake of magnitude 6.9 devasted the island. Strong aftershocks continued to rock the Indonesian island, quickly transforming the popular tourist paradise into “hell on earth”.

In an episode of Channel NewsAsia’s Insight titled "Lombok: A Shattered Paradise", aired on 7 September 2018, Prof Sieh provided insights on how tectonic plate movements could result in tsunamis, volcanic activities, as well as devastating earthquakes. Using the analogy of a cracked windshield on a car, Prof Sieh explained how aftershocks are produced from faults during an earthquake. In some instances, an aftershock can trigger a more powerful earthquake. This is possibly what...

Submitted on 14 Nov 2018 by:

On Sunday (29 July 2018), I learnt about the strong 6.4-magnitude (M) earthquake in Lombok, Indonesia. As we have friends living there, I wanted to visit to see what aid we could organise for the people there. So my husband and I went to Lombok with some friends, and we linked up with other humanitarian aid groups to visit the Sembalun area, which is about 1,000 metres above sea level, at the foothills of Mount Rinjani, one of the most scenic volcanoes in the world.


At about 6.46 pm the following Sunday (5 August 2018), just as we had finished a meeting to prioritise the relief needs, an earthquake suddenly occurred. It was my first time experiencing a quake, and it really shook the foundations of what I knew about them.

I realised I had many...