Earth Observatory Blog

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 15 Feb 2021 by:

A Mw 7.1 earthquake struck Japan on 13 February 2021 at approximately 11:07pm (Japan local time). According to the United States Geological Survey, the earthquake occurred at a depth of about 50 kilometres (km) and about 70 km from the town of Namie, off the east coast of Honshu. The event was widely felt, injuring more than a hundred people and damaging some infrastructure.

“This earthquake is not particularly unusual or unexpected for this region, but it is noticeably larger than most recent events this deep and this close to the coast,” said Dr Kyle Bradley, a Principal Investigator at the Earth Observatory of Singapore (EOS).

The event is another likely powerful aftershock of the Mw 9.1 event

The event occurred nearly 10 years since the Mw 9.1 Tohoku...

Submitted on 29 Jan 2021 by:

A series of deadly earthquakes struck the Indonesian island of Lombok over three weeks in August 2018, causing widespread damage. These earthquakes were unusual because there were two magnitude-6.9 mainshock events that were each preceded by a smaller foreshock, instead of a single mainshock. The complexity of the earthquake sequence caused great anxiety about when another powerful earthquake might occur.

In our study published in the journal Science Advances, we demonstrate how the complexity of this earthquake sequence is due to the influence of Gunung Rinjani, Lombok’s large active volcano, on the geological fault that hosted the earthquakes.

After the first powerful magnitude-6.4 earthquake...

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 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 08 Jul 2020 by:

A commentary by Professor Benjamin Horton (Earth Observatory of Singapore) and Emeritus Professor Perter Horton (University of Sheffield), published online on 7 July 2020 in One Earth, looks at how the current COVID-19 pandemic and the climate crisis are signs of the unsustainability of human society and the decreasing resilience of our ailing planet.

Titled “COVID-19 and the Climate Emergency: Do Common Origins and Solutions Reside in the Global Agrifood System?”, the authors discuss whether both events have the same underlying causes and common solutions, and whether they might be rooted in a failing global agrifood system.

Citing declining...

Submitted on 02 Jul 2020 by:

On 22 December back in 2018, Indonesia’s Anak Krakatau volcano erupted. The collapse of its flank triggered a tsunami that killed more than 400 and injured at least 30,000 people. 

To understand how the events of that day unfolded with such catastrophic effect, an international research team led by Research Associate Anna Perttu from the Earth Observatory of Singapore (EOS) turned to the data collected from monitoring stations from all around the region, official reports, as well as satellite and visual observations.

Eruptions produce a wide range of signals. Humans can see and hear some of them only when close enough to the eruption. Monitoring instruments help fill the gap. Satellites can be used to image volcanic plumes that are too high or obstructed from an...

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...

Submitted on 15 Jan 2020 by:

As at 5 pm on 15 January 2020, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that Taal volcano’s eruption is still going on and retained the Alert Level for Taal at 4 (hazardous eruption imminent), where further eruptions are likely to occur in the coming hours or days.

The volcano continues to send dark grey steam-laden volcanic plumes up to 700 metres (m) in height drifting to the southwest of the volcano, and new cracks on the ground have been reported in several locations around the volcano. New observations indicate that the Main Crater Lake and parts...