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Tracking and Finding Patterns to Earthquakes

Decent Essays

Marmara Region of Istanbul has a history of catastrophic earthquakes such as the ones that struck on 17 August 1999 (Mw=7.4) and12 November 1999 (Mw=7.2). This led to the introduction of Istanbul Earthquake Rapid Response and Early Warning System (IERREWS) as a preventive measure for future earthquakes occurrences. This system consists of a dense network of 100 strong motion recorders located in the metropolitan area of Istanbul, 10 near the Great Marmara Fault and 40 more located at important structures (Mert et al 2004). The early warning system of the (IERREWS) is based on exceeding of predetermined thresholds values for the peak ground acceleration (PGA) and Cumulative Absolute Velocity (CAV) it has three alarm levels. If the value of CAV exceeds the threshold value it is considered a vote and within a specified time interval if the threshold value is exceeded in 2 or 3 stations the first alarm is declared. The original CAV has been modified to Bracketed CAV (BCAV) which is a summation of the maximum acceleration value exceeding a threshold value within a specific time domain generally at a one second interval. A recently modified version of the BCAV called the Windowed Bracketed CAV (BCAV-W) has been suggested which integrates the maximum acceleration values for a window length of 8 seconds. For the bracketed CAV window the threshold values suggested for the three alarm levels are 0.20, 0.40 and 0.70 m/s (Alcik et al 2009).

2.5 ElarmS:
The ElarmS algorithm is a

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