Earth Observatory Blog

Submitted on 30 Aug 2021 by:

In this interview series, we learn about the perspectives of the PhD students whose wide-ranging work contribute to the SEA2 Program and share what drives them in their research.

Underground sediments can serve as geological libraries that offer a glimpse into past environments such as bygone mangrove ecosystems and shorelines.

For one PhD student, in particular, this study into proxy indicators of sea levels in the last 10,000 years is a way of amalgamating his love of mangroves and recent interest in sea-level rise. Proxies are organic materials that can be carbon-dated to serve as age markers in paleo-climate science.

Yudhishthra Nathan, a second-year...

Submitted on 26 Aug 2021 by:

In this interview series, we learn about the perspectives of the PhD students whose wide-ranging work contribute to the SEA2 Program and share what drives them in their research.

The past sea levels of the Holocene period can be reconstructed via the use of paleo-proxies, including the use of mangrove sediments, which contain organic materials that can be carbon-dated and serve as age markers and one person working on such historical records is Christabel Tan, a second-year PhD student on Professor Benjamin Horton’s research team. 

Collecting sediment core data for her thesis at Pulau Ubin, she studies and analyses their contents to help fine-tune sea-level...

Submitted on 19 Aug 2021 by:

Bangladesh, a densely populated country of over 160 million people, regularly faces climate hazards caused by flooding and typhoons. However, another natural hazard lies silently beneath the country: active tectonic faults. The fault system below Bangladesh is estimated to be able to generate an earthquake of magnitude 8.5 or greater – a phenomenally dangerous possibility, given that it lies only a few kilometres below the surface. Such an earthquake would also trigger secondary hazards: liquefaction, flooding, and possibly even abrupt shifts in the course of rivers. Despite its extreme hazard, this fault system remains poorly understood.

Bangladesh sits on the eastern border of the collision zone between India and Eurasia, where the Indian plate is subducting eastward...

Submitted on 13 Jul 2021 by:

In a world largely driven by technology, the Global Positioning System (GPS) is ubiquitous. Best known for providing positioning, navigation, and timing services, the incorporation of this system into smartphones and smartwatches has made it almost indispensable for many.

Scientists at the Earth Observatory of Singapore (EOS) have explored the use of this system for climate research by observing the amount of water vapour in the atmosphere. Atmospheric water vapour, albeit invisible, plays a crucial role in shaping the Earth’s weather and climate.

GPS radio signals travel from GPS satellites at an altitude of ~20,000 kilometres to ground receivers through the Earth’s atmosphere. Because of its physical properties, the atmosphere slows and bends the GPS signals. As...

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...

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