A multidirectional look at the phenomenon of earthquake

In December 1993, CP Rajendran and his wife Kusala, travelled to Desamangalam, near Wadakancherri in Kerala, to assuage the fears of villagers whose lives had been upended by a long procession of aftershocks following a relatively harmless earthquake. Land prices had dipped drastically, men from the village found no suitors, and people had been sleeping in the open for months.

After they arrived in the village, the couple was felicitated on a makeshift platform. Then, just as Rajendran drew the villagers’ attention to the reduced frequency of the aftershocks, advising them to not get too perturbed, the earth, perhaps wryly, rumbled again.

The young, unsure science of earthquake prediction is one of the several subjects examined by the country’s top seismologists in their new book, The Rumbling Earth: The Story of Indian Earthquakes. “As of today, there are no models that can predict the time, place and sizes of future earthquakes. Neither their causative factors nor their interactions are observable, unlike atmospheric processes that can be monitored,” say the authors.

The mercurial nature of earthquakes is perhaps best illustrated by the Parkfield Experiment of 1993, for which hundreds of geologists besieged the little town in California. Situated on the San Andreas fault, one of the world’s largest faults, Parkfield had experienced a 22-year regularity of moderate earthquakes since 1857, and was the site of an earthquake prediction experiment led by the United States Geological Survey. But nothing of note happened that year. Instead, the earthquake arrived 11 years later in 2004.

The Rajendrans, who discovered their shared passion for Earth sciences in the late 1980s while pursuing their post-doctoral studies in Charleston, US, have an intimate familiarity with the earth and its major upheavals. In The Rumbling Earth, they tell their story unselfconsciously, at a brisk pace, toggling between mole’s-eye views of the elemental forces of nature at work under our feet, and through paleoseismology, which reconstructs the history of earthquake activity before instrumental recording began, unravelling evidence of ancient tumults that could portend future seismic hazards.

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