Fighting quakes with computers
In today’s world of modern technology, one wonders if computers could not have warned about the October 8 earthquake.
However, there is no high-tech system in the world to give warnings about earthquakes and assess its exact timing but there must be a technology that could help lessen the damage. Earth changes could be monitored regularly using modern technology.
“We are arranging an international conference on seismology in Islamabad on March 6 to 8, 2006. The conference will discuss many topics, including the role of computers in warning people about earthquakes well in time,” Dr Qamaruz Zaman Chaudhry, the Pakistan Metrological Department director general, told Daily Times.
Assumptions are made on the basis of data collected through monitoring earth movements through highly sophisticated computerised instruments. Computers hence play an important role in the field of seismology. Seismograph, an instrument used for recording the intensity and duration of an earthquake, is a computerised output device.
Sophisticated computers have already been installed in many advanced countries to record tele-metered seismic signals in real time by radio and landlines. These computers are centred on remote seismic stations in a particular region. Real time computer systems at each centre continuously monitor earth movements for earthquakes.
When an earthquake occurs, seismic waves are created, which move away from the epicentre. The fastest shock waves, termed as P-waves (Pressure waves) travel outward at a speed of about three to five miles a second. As the P-wave passes each seismic station, its arrival time is detected and noted by the computers. These computers use the list of arrival times to determine the location of the earthquake. The location is typically available within a minute or less after the occurrence of the earthquake. Although predicting a quake is not possible, once they do occur the information could be disseminated swiftly if a proper system was in place.
Many websites provide detailed information about earthquakes. When the location of a new earthquake is known, a signal is sent to a particular computer that updates the website, meant exclusively for such purposes.
When a potentially significant earthquake occurs, as determined by pre-defined criteria, a computer, specifically programmed for this job, alerts the duty seismologist by a radio pager. The seismologist logs in to the computer, reviews the automatically determined location and magnitude and notifies the appropriate emergency response centre. Japanese scientists knew about the October 8 quake from their monitoring station immediately after its occurrence in Pakistan. Circulated on time, this real-time report could save human lives.
In order to estimate future earthquakes, one would have to study how fast strain accumulates on the layers of the earth. When the strain, created by plate movements, reaches a certain level, the rocks will break and slip to a new position. Scientists use computerised monitoring tools to measure how much strain is accumulating along a fault segment each year, how much time has passed since the last earthquake along the segment, and how much strain was released in the previous earthquake. Extremely weak predictions could be made about earthquakes based on the past frequency of large earthquakes. The Southern California Earthquake Centre (SCEC) has been developing a high-tech system that will lead to better forecasts of earthquakes.
Source: Daily Times
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