Can there be an early warning system for an earthquake?
January 7, 2014
My comment: I think that there can be, because the earthquake is not a result from an organic process, apoptosis, mitos etc, not even about organic mass of material – but results of physical components of anorganic energy in and to the anorganic mass of the Earth. of caus its very multifunctional calculation with need of extremely much data input. How to predeict where the compression should appear next time.
“Geophysicists in the US have developed a new way of calculating the magnitude of an imminent earthquake by making better use of measurements of the compression waves produced early in the event. They say that the technique could be used to create a better early-warning system for earthquakes that could be used worldwide.
The majority of earthquake damage is caused by S-waves, which oscillate perpendicular to their direction of travel through the Earth, and by waves that occur on the surface. However, these are preceded by much faster-moving compression waves (called P-waves) that oscillate in the direction of travel and cause minimal damage. By making careful measurements of arriving P-waves, seismologists can get some idea of the strength of the impending earthquake. While this only gives officials tens of seconds to react, it is enough time to take some protective action such as slowing down high-speed trains, switching off gas mains and even warning the public to seek shelter.
Amplitude, period or both?
Current early-warning schemes make use of two properties of P-waves: the displacement amplitude of the P-wave’s vertical component (Pd) and maximum predominant period of the P-wave (τpmax). To understand how best to use these measurements, Huseyin Serdar Kuyuk and Richard Allen of the University of California, Berkeley looked at real-life data recorded from 1992 earthquakes processed by California’s real-time Earthquake Alarm Systems. They also looked at 174 earthquakes in California and Japan that have already been used in early-warning calibration studies. The earthquakes they studied varied in magnitude (M) from 0.2–8, with M = 8 being a major earthquake.
The team used these data to test five different methods for calculating Earthquake magnitude. The techniques use either Pd, τpmax or both to make their predictions. Some of the methods are already used in early-warning systems and one is a new technique developed by the researchers. The team found that its new technique – which is based on Pd measurements alone – gave the most accurate and robust estimate of earthquake magnitude. In contrast, methods that used τpmax did not do a good job of predicting the magnitudes of small earthquakes (M < 3). They were also less accurate than Pd-based techniques for larger magnitude events.