'The Rumbling Earth' book review: 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.
Their work has taken them across the ‘ring of fire’ or the Circum-Pacific belt, the world’s most seismically and volcanically active zone, but the duo has always had an ear to the ground in India. In 1993 in Killari in Latur, they attempted to understand the reasons behind the “bolt from the blue” earthquake in a region with the least seismic activity. With over 8,000 deaths, it “is a classic example of how the perception of low-level seismic inactivity proved disastrous”, write the authors.
“Similar earthquakes have been reported from various continental regions... These earthquakes are not instrumentally recorded, but presumably, they must have past histories of similar earthquakes. Therefore, they make suitable candidates for geological investigations in the search for events in the past.” The seismologists were also there in Jabalpur in 1998, Chamoli the next year, and in Bhuj in 2001… And they’ve roamed the Himalayas and the eastern Indian coastline scrutinising old temples, historical monuments and ancient literature for signatures of past earthquakes and, often, tsunamis.
After the 2004 tsunami, the Rajendrans travelled to Mamallapuram and Kaveripattinam, the great port of the Cholas. “Trenches excavated in Kaveripattinam exposed evidence of a previous sea incursion in the form of tsunami deposits of the same vintage as at Mamallapuram. Interestingly, an early South Indian literary work, Manimekhalai, by a Buddhist poet named Seethalai Saathanar, mentions the ‘angry’ sea. He writes that the sea ‘swallowed’ a part of the ancient port city of Kaveripattinam. Could this be an ancient tsunami?” the authors write.
At times, like the rest of us, they also sit back and stare in wonder at the handiwork of great upheavals, like the 1819 Rann of Kutch earthquake. With a magnitude of 8.2, it destroyed 7,000 houses in Bhuj and Anjar, and killed over 1,500 people. It also violently redrew the topography of Kutch, leaving behind, as a brutal reminder,a mound that rose between two and four metres off the ground, and stretched for 90 kilometres across the Greater Rann. The villagers named it Allah Bund, or the ‘mound of God’.
So, how does one prepare for the inevitable? The Rajendrans point towards countries such as Chile, which is considered to be a global model for earthquake preparedness and response. They also worry about the Himalayas, and it is not just restricted to the great earthquake in the central Himalayas that has been awaited with foreboding for over three decades. The rampant infrastructure development in the region, and China and India’s race to build massive hydroelectric projects in the area deeply concerns the authors. While China has completed 11 out of the 55 projects it had drawn up for the Tibetan region, the Indian Himalayas have accommodated 81 large hydropower projects, with another 26 reportedly under construction.
“The unique Himalayan landscape with steep slopes and sharp gradients is not inherently amenable to human engineering... The threat is grave when construction occurs in active seismic zones, which may also coincide with areas of high population density,” say the authors. The recent land subsidence reported from Joshimath, they add, is a serious warning we would do well to pay heed to.