The devastating earthquake of magnitude 7.7, which hit Balochistan recently and took a lot of lives, gave rise to a weird mound of earth, about 20-40 feet high and 100 feet wide. The island emerged around 350 feet away from the Gwadar coast. This strange piece of land soon attracted geologists, who later concluded that it’s probably a mud volcano.
Well, earthquakes happen at various places then why this island appeared in the northern part of Arabian Sea after this earthquake in particular? That’s what fascinated me to read, and write for the first time 😛 I’m not a geologist or a fan of geology, so whatever I’m going to write is my general understanding 😛
What exactly are mud volcanoes? They are never permanent and erupt as soon as the gas reaches a sufficient pressure. The exact mechanism of their formation is, however, not clear but key features are either enormous submarine sediments or presence of hydrothermal fluids such as petroleum or gas hydrates. Mud Volcanoes are in fact a common phenomenon in sea as well as on land, and predominantly occur along faults, fault-related folds and anticline axes.
The Earthquake in Baluchistan was caused at a fault of about 15 km depth at Makran subduction zone. This is the zone where tectonic plates dive beneath one another and world’s strongest earthquakes occur at these places. Earlier in November 1945, this zone was struck with a magnitude 8.1 earthquake leading to one of the worst tsunami events in the region. Now the same zone was the origin of a 7.7 magnitude earthquake. This is an ideal site for mud volcanoes because of enormous submarine sediments that, when shaken up by the earthquake, erupted into an island which consists of mainly mud and sand along with dead sea life, decomposed into methane gas. The locals have observed bubbling which is sign of emission of methane.
As the history depicted, the geologists were of the view that it would not last long as such islands vanish away with the passage of time. Now reports are showing up that the island has started to sink. Let’s see how much longer it remains on surface 🙂
By Hafsah Akhtar, SMME