Tezpur/Dhekiajuli, April 29 : The state has been facing a series of strong and mild earthquakes since Wednesday morning with a magnitude ranging from 3 to 6.5 on the Richter scale. Geologist Dr Achintya Kumar Das from KADlien investigated two sites in the Sonitpur district namely Kalakuchi in Misamari and Kailajuli in Chariduar from where fracture accompanied by water spings were reported. Initial field observation gave evidence of a very rare and interesting phenomenon of earthquake-induced liquefaction which is technically known as Sesmites. As a result of which there have been ejections of sand and water from the cracks or multiple fractures. Close observation also suggests that source of these sand ejections are probably from a shallow sand bed along with a water table which is situated 2 to 3 feet or deeper beneath the earth surface. The length of these kinds of multiple fractures are as long as 200 to 300 metre or more in some areas. Initial studies show that the ejected particles are fine sand or sand silts.
He further informed us that they are in contact with Department of Geological Sciences in Gauhati University and samples will be sent for further laboratory investigations including Thermo – Luminescence Dating.
He said that earthquakes are generally due to plate tectonics activities. The active Kapili fault is probably responsible for these earthquakes. Geologists generally study these kind of rare instances of Semites or liquefaction to understand past history of earthquakes where instrumental records are not available.
Dr. Achintya Kumar Das is currently Director of KADlien. Earlier, he worked as a Geoscientist in Halliberton and Slumberger in Middle East and Asia Pacific regions as well as in India. He did his PhD from GU under renowned Geologist B P Duara on Paleo-Seismology.