By Kota Sriraj
The last six months have been witness to a surge of seismic activity across the world. At least 400 earthquakes of magnitude-five and above were recorded across the world in December 2016 alone, marking an increase of three and a half times the monthly average. As recently as February 6, a quake of 5.4 on the Richter scale hit Uttarakhand, and Colombia and Turkey.
The increasing frequency of earthquakes has become a major concern and the need to find the underlying causes is now very crucial.
As the research into the unusually high rate of seismic activity gained momentum, scientists in November 2016 found out that the abyss under the Pacific Ocean between Indonesia and Papua New Guinea was left behind by a massive earthquake during the last Ice Age, making it the world’s largest exposed fault. Termed as the Banda Detachment Fault, it is seven kilometres deep, 450km long and covers an area of 60,000 sq km. The discovery has not only evoked the curiosity of the global research community but also confirmed that the earth’s crust is active and moving.
Several research studies are now pointing to the fact that one of the major causes for the high seismic activity might be climate change and the deteriorating state of environment. Stark changes in earth’s atmosphere are now playing a role in geological processes. In a paper published in the journal, Nature, researchers drew a link between typhoons in Taiwan and small earthquakes in the region. The study pointed out that the rapid drop in atmospheric pressure before a storm allows faults in the crust to move more easily and release accumulated strain.
In the Himalayas too, there is an unmistakable link between seismic activity and changes in the hydrological balance of the region. The hydrological cycle being the flow of water in and out of a system through rainfall or snowfall and evaporation, among other processes is being now severely disrupted due to climate change.
This intervention with the existing hydrological balance is causing glacial melts and extreme rain events, resulting in a domino effect by changing the load of water and ice on the surface, which in turn triggers seismic activity.
The Arctic is already bearing the brunt of climate change, and ice sheets are melting at such alarming rates that the Arctic Circle might have no ice by 2030. According to research studies published in Science Advances in September 2016, Greenland, for instance, has been losing about 272 billion tonnes of ice a year over the past decade. GPS measurements show that Greenland and its surrounding region have risen by four to five meters due to the loss of ice load. This movement has been linked to several small earthquakes in the region, which was considered inactive.
Climate change and degrading ecological conditions are now becoming a triggering point world wide for earthquake as the accumulated stress in the earth’s plates are being released due to the impact of rising temperatures. In addition, anthropogenic actions like petroleum extraction and deforestation are playing havoc with the earth’s crust, leading to a rise in quake related incidents.
The Pioneer, February 10, 2017