The Unpredictable Seismic Risks

TOPSHOTS Myanmar residents gather as they inspect large cracks on a road two days after an earthquake struck the area, in Tarlay township near the northeastern city of Tachilek on March 26, 2011. Survivors surveyed the wreckage of their Myanmar villages as details of an earthquake that left 75 dead and reduced homes to rubble began to trickle out of remote areas.    AFP PHOTO/ SOE THAN WIN

Courtesy: AFP PHOTO

Animals are said to have accurate detection abilities, when it comes to predicting earthquakes. It is proclaimed that some herds of animals behave weirdly since they sense changes (chemical) in ground water from an impending earthquake. Although the strange animal behavior may remain valuable with respect to predicting earthquakes, statistically & practically, there are huge hardships in linking the unusual behavior with that of impending disaster. The vital question rose after every major, bloodcurdling seismic catastrophe remains the same: Why with all these high-end technologies, the seismologists couldn’t accurately predict earthquakes?

The simple answer provided different scientists are the same: we don’t know enough about plate tectonics. It is said that, unlike other sciences, we are still on the learning phase with plate tectonics. So, it might take decades to get into something as elusive as prediction. Apart from electromagnetic energy, chemical changes in groundwater & wildlife behavior, the most practical method carried out is identifying quake timing patterns, using historical records. But then, the big problem with this method is that geologists were only able to collect 100 or 150 years of hard data, whereas some major earthquake cycles span thousands of years.


Another general option is to study the faults, but this method could only to give a probability. For years, scientists thought there is a high likelihood of an earthquake near Kathmandu or in the Himalayas. But, the seismologists being right haven’t lessened the horrific disaster, happened in Nepal. Currently, the prediction going around is that there will be a major earthquake disaster in California (close to magnitude 8 and the probability is percent). The other major problem in studying faults is predicting the magnitude. The 2011 Japanese earthquake recorded 9.0 on Richter scale. The general scientific consensus was that the fault could only produce a earthquake of magnitude of 7 or 7.5.

Seismologists state that on a logarithmic scale, magnitude 8 is 100 times powerful than a 7; similarly a magnitude 9 is 10 times powerful than 8. Japan is known for staying alert with regard to earthquakes. Japanese government’s scientists for years (after the ‘Great Kanto Earthquake of 1923) have believed that earthquakes aren’t random; they follow a pattern and withhold some precursors. But, the 2011 earthquakes even defied the expectations of Japanese seismologists (note that the Sumatra had been considered an unlikely source of a great earthquake in 2004). More often, Japan not only predicts earthquakes; it also gives a name to its next big earthquake, approximately stating the epicenter and the number of deaths.

Seismic zoning Map of India  Pic

Seismic zoning Map of India

It is also often believed that small swarms of quakes would never result in a large one. However, the 2009 L’Aquilla (situated northeast of Rome) earthquake poked a hole in this theory too. Even a government official of the city is said to have told press that small seismic swarms had reduced the danger of a major event. In the end a 6.3 magnitude quake claimed the lives of nearly 300 people, injuring at least 1,500 people. The public’s outrage immediately focused on city’s seismologists. Six scientists were charged with manslaughter for not the predicting L’Aquila earthquake, and the judge found them guilty by handing down a sentence of six years. Scientists all around the world condemned this case as a ‘medieval witch hunt’, ‘unfair’, and ‘naive’. After two years of appeal, the scientists were acquitted from the charges.

Humans’ fixation on predicting earthquakes has started ever since we have started to live inside structures that could fall upon us. For now, we are still in the dark to know about a hypothetical natural disaster that might occur once or twice in a century. However, as always, science could eventually provide betterment & hope.


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