Earth Observatory Blog

Submitted on 18 Jun 2021 by:

Coastal communities face several hazards including tsunamis triggered by offshore earthquakes and volcano eruptions as well as storm surges generated during tropical storms.

Deposits left behind by these events provide important clues for the reconstruction of past events, enabling scientists to correctly forecast the risk posed by tsunamis and storms. This knowledge is of paramount importance for the estimated 600 million people living in coastal areas below 10 metres (m) above sea level.

One long-standing challenge has been to differentiate between sediments laid down by these storms and tsunamis. For more than 30 years, scientists were unable to distinguish between the deposits using regular methods such as sediment analysis and micropalaeontology.

But...

Submitted on 15 Jun 2021 by:

In April 1991, the authorities in the Philippines began evacuating people from their homes located within 30 kilometres (km) of Mount Pinatubo. More than 60,000 people were evacuated by early June 1991. This huge undertaking came after recommendations from the Philippine Institute of Volcanology and Seismology (PHIVOLCS), and the US Geological Survey (USGS). 

Pinatubo had not recorded any eruption in the past 500 years, yet just a few days after the evacuations, the first explosive eruptions of the volcano in centuries took place.

On 12 June gas-charged magma reached the surface of Pinatubo, creating a series of explosions that formed spectacular...

Submitted on 08 Jun 2021 by:

Did you know that the coral reefs of Southeast Asia account for a third of the world total? Spanning an area of 100,000 km2, these reefs are rich in biodiversity and provide critical services to coastal communities, including fisheries, tourism, and coastal protection. 

While reef health and resilience are often measured by metrics such as the amount of coral on a reef or the number of different species, the quality of the coral skeleton itself is also a critical part of the services reefs provide. In Singapore, we found that some coral skeletons deformed and fractured more easily than their counterparts from other reefs, which may make them more vulnerable to climate change.

As corals grow, they deposit calcium carbonate crystals underneath their tissue, building...

Submitted on 20 May 2021 by:

The Himalayas rise and sink in a relentless cycle driven by geological forces. In an interview with National Geographic, Assistant Professor Judith Hubbard, a Principal Investigator at the Earth Observatory of Singapore, compares the evolution of the mountains to our breathing cycle.

The mountains rise, or inhale, due to the forces generated as the Indian plate moves northward and collides with the Eurasian plate. They subside, or exhale, when an earthquake happens. The exhalations can be of different intensities, from violent coughs – strong earthquakes – to hiccups – smaller earthquakes. This illustrates the seismic cycle: a complex...

Submitted on 15 May 2021 by:

A strong earthquake struck the Nias region off the west coast of Sumatra, Indonesia, on 14 May 2021 at approximately 1:33pm (Singapore time). According to the United States Geological Survey (USGS), the magnitude-6.6 earthquake occurred at a depth of about 10 kilometres.

Based on information provided by the USGS, yesterday’s earthquake occurred within the Indo-Australian plate, where it bends before subducting under the Eurasian plate. As the plate bends, it can break and generate what is known as an outer-rise earthquake.

Yesterday’s earthquake is not a megathrust event as it did not occur at the boundary between the two tectonic plates, unlike the 2004 Great Sumatran earthquake. "It demonstrates how subduction zones are not just simple plate boundaries but...

Submitted on 06 May 2021 by:

The magnitude-9 earthquake and associated tsunami that hit Japan in March 2011 illustrates the devastating power of earthquakes from subduction zones – boundaries where two tectonic plates converge, as one plate dives beneath the other. These are earthquake-prone regions that pose a threat to millions of people worldwide, especially in Southeast Asia. To help forecast such hazards, two new studies from the Earth Observatory of Singapore (EOS) investigated how these subduction zones work. The studies, published in Nature Geoscience, show that existing hazard assessments from subduction zones worldwide need to be updated.

Earthquake and tsunami assessments mostly rely on our knowledge of past events and of physical processes describing how one plate dives under the other...

Submitted on 21 Apr 2021 by:

Visitors to the Earth Observatory of Singapore (EOS) will be familiar with the exhibition of polar and tropical marine wildlife by some of the world’s leading photographers.

The driving force behind the ‘Elysium Epic Trilogy’ exhibition is Mr Michael Aw, the entrepreneurial underwater photographer who organised three expeditions to the Arctic, Antarctic, and Coral Triangle to document the species featured in this unique exhibition.

The locations of three disparate Elysium expeditions share one common feature – they are all in the front line of climate change. Of his experiences in the Antarctic, the Arctic, and the Coral Triangle, Michael set the scene: “It is humbling and challenging because we can see what we will lose and how much or how little we can do about...

Submitted on 12 Apr 2021 by:

The magnitude-6 earthquake that struck Java on Saturday, 10 April 2021, at approximately 2pm (local time) occurred at a depth of 82 kilometres (km), according to the United States Geological Survey. This earthquake was strongly felt in East Java and led to loss of life and property. The location of this earthquake is the main reason why it was felt so strongly.

The earthquake occurred about 60 km southwest of Malang, off the coast of Java, a region where the Indo-Australian plate dives under the Eurasian plate. In this region, the subducting plate experiences downward-pulling forces. It also experiences increasing pressure and temperature, which cause hydrous minerals to release water. These processes work together to cause the deeper part of the slab to break and...

Submitted on 06 Apr 2021 by:

In conversation with Assistant Professor Judith Hubbard, Principal Investigator at the Earth Observatory of Singapore

1. Why it is important to understand tsunami generation? Recent earthquakes in New Zealand triggered tsunami warnings along coastal communities, yet no tsunamis resulted. Why was this so?  

These recent events in New Zealand highlight the fact that tsunami warning systems have to do two things: first, they have to identify which earthquakes can produce tsunamis, and second, figure out which earthquakes won’t. This is difficult to do because the process of tsunami generation is complex and depends on a lot of factors.

In general, when people talk about an earthquake, they are referring to the shaking that we feel as a result of a...

Submitted on 26 Mar 2021 by:

Ostracods are aquatic crustaceans that range from 0.2 to 30 milimetres in size. Did you know that that these tiny creatures, also known as seed shrimp, can be used to indicate the pollution levels in lagoons in Southeast Asia?

This is the main finding of our new study published in Environmental Pollution, which uses ostracods collected from a coastal lagoon in Vietnam.

Ostracods produce a skeleton on the outside of their bodies that consists of two valves that open and close like a mussel shell. The shells are formed of calcium carbonate and are easily fossilised in the sediments in which they live. Ostracods first appeared 485 million years ago and their species can be found in a wide...

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