Making much ado about earthquakes

Most educated people are used to sipping tea and reading a newspaper in the morning. If other family members are sitting in the same room, they sometimes exchange news. Disaster-related news is one of the big sources for initiating a discussion. Earthquakes which occur suddenly have a priority over volcanoes, which give some indications of an eruption.

The magnitude scale of earthquake is logarithmic and it is possible to have zero and negative magnitude earthquakes. In seismological lexicon there is a magnitude-wise gradation. Unnoticeable (less than 2), weak (2 to 3), light (3 to 4), felt (4 to 5) and moderate (5 to 6). Above 6, everybody feels the seismic shaking.

It has been observed that much of the electronic media and sometimes, even the print media disproportionally magnify the seismic parameters. When the Latur earthquake occurred in 1993, early reporting of the death figure was as high as 70,000. Subsequently, this went down and ultimately it was officially pegged at 10,000.

Prior to 1960-65, most of the seismological instruments were able to record a minimum magnitude of 4.5 or so. With the advancement of electronic instruments, the detection potential of the instruments has increased and they can also record zero and negative magnitude earthquakes. The Richter scale is logarithmic, as such there could be zero and negative magnitudes.

With a large number of advanced instruments installed at various locations such as power plants, dams and industrial units, the number of small earthquake records per day increased exponentially. Maharashtra's Koyna region is moderately active seismically. After the 1967 moderate earthquake, there is no record of any sizable earthquake. But it records several small earthquakes of the 2.0 to 3.0 range.

Incidentally, these are reported after several hours in the press and also on television. After hearing the news, I receive several calls enquiring about seismic safety. Every time I have to tell the callers not to fear or bother. The Idukki dam authorities had published a report about 10 years back and it has documented about 1,50,000 earthquakes. Of these, only four were in the 4.5 to 5.0 range.

There were thousands of earthquakes below magnitude zero. When this was reported in the newspapers, a leading literary lady personality asked: "Is the Kerala government sleeping?" At that time I was the chairman of a committee of the state government.

I was asked for suitable reply. I said I would visit capital Trivandrum (now Thiruvananthapuram) and pitch a tent in front of that individual's house and would create an earthquake every minute. If a 5x10 brick of 20 cubic centimetres is dropped from a height of two metres, the impact is equivalent to magnitude 1.0 quake. That silenced the matter.

After the December 26, 2005, earthquake and tsunami I was camping in the Andamans in February 2006. I received a telephone from the Gujarat government saying that a volcano has erupted in the state and I should immediately inspect the site. I went there with all the necessary paraphernalia for chemical tests of the so-called volcanic material. I was shown a thick file of clippings on the danger of an eruption. There were at least a dozen television vans following our motorcade.

The local people gathered and started shouting about the daily noise of an eruption. They showed me four mouths of "volcanoes" about 15 cm in diameter and about 7 cm deep. These "volcano mouths" were just below an 11 kV High Tension cable. I could immediately decipher the volcano story. In villages, it is not unusual to steal electricity with hooks attached to a tall bamboo. When the wire is tapped in this way it trips and falls down, making a deafening noise. The ground below was basalt and the cable caused a hole.

The story was repeated at the Kudamkulam Atomic Power Plant. When its erection was opposed by people and supposedly funded by foreign organisations, I was requested to examine the report submitted by these people. The report said that there were four volcanoes within 20 km of Kudamkulam. It turned out to be a repeat story of Gujarat's so-called volcano.

I was on tour to Kanyakumari in 2006. During the wee hours, I received calls from three TV channels asking my opinion about the rumors being highly circulated in Gurdaspur and Bhatinda of an impending huge earthquake. I was also told that the rumors had originated from a neighbouring country and a large number of people have received telephone calls. I totally refuted it. Subsequently it was reported that this was a ploy to camouflage the entry of militants.

The reported news about an earthquake in Bengaluru on April 18 falls in this category. It was said to have been felt on the outskirts of the city and in Mandya, Tumkuru, and Kollegal et al. There was nothing recorded on any seismic recorder. It could well be due to quarry blasting or the collapse of a mine roof. During the past two to three years, there have been accidental explosive blasts at army ammunition depots at Pulgaon (Maharashtra), Jabalpur and Pune. These were also reported as big earthquakes.

It clearly shows the excessive craze of press reporters to hunt for any kind of sensational stuff. This disproportionately amplified to create breaking news. The reporters feel that they have done a very big job. But this is simply indulging in narcissism. I would sincerely request all concerned to avoid such blowing up of news. This only enfeebles the reporter's name and fame. They must throw away their misdirected obsession with sensation. (Writer is a prominent seismologist and former head of Earthquake Engineering Research, Central Water and Power Research Station, Pune)

By Dr Arun Bapat