Earth Observatory Blog

Submitted on 11 Mar 2017 by:

The devastating 2011 Tohoku earthquake in northeastern Japan was a record-breaker on many levels. The magnitude-9.0 quake was Japan’s largest recorded and the world’s fourth biggest earthquake since 1900. Most terribly, it unleashed a 39-metre high tsunami, killing almost 16,000 people and causing a nuclear meltdown at Fukushima Daiichi Nuclear Power Plant.

The earthquake had effects on a global scale. Seismic waves caused icebergs to break off in Antarctica, water in Norwegian fjords to splash back and forth, and wreckage from the tsunami washed up along the North American coastline. Another global consequence? The quake shortened Earth’s day by 1.8 microseconds (µs) and shifted its figure axis by 17 centimetres (cm). 

Just to clear things up, our planet...

Submitted on 29 Nov 2016 by:

In the night of 21 November 2016 (local time), Japan was struck by a magnitude-6.9 earthquake. This was soon followed by a M 5.6 quake in New Zealand’s North Island, which sparked speculation that the event in Japan had triggered the one in New Zealand. 

Dr Wang Yu, a Research Fellow at the Earth Observatory of Singapore, appeared on Channel NewsAsia’s morning news programme, on 22 November 2016, to explain both earthquake events, as well as clarify whether or not this is an indication of more large earthquakes to come.

Below is a short summary of the Q&A segment between Dr Wang and host, Christine Chan:

Q: First Japan, then New Zealand. Are we seeing an awakening of the Ring of Fire?

The Ring of Fire never rests. If we look at historical...

Submitted on 27 Apr 2016 by:

The concept behind a theme park’s Tipping Bucket water game is simply this: water drips slowly into a bucket and when it becomes completely filled, it tips over to splash the people beneath it.

An earthquake fault acts in the same way. Tectonic stress from a plate’s motion gradually accumulates on the fault plane until it hits a critical level, causing the fault to rupture and generate an earthquake. 

Similarly, one could look at a fault system as being made up of many tipping buckets of different sizes with different filling rates, and containing different amounts of water. When a big earthquake occurs, the ruptured fault will transfer some degree of tectonic stress to nearby faults. To understand this, imagine a large bucket of water tipping over and splashing its...