ALBERT

Beschreibung: INTRODUCTION Rapid detection and characterization of earthquakes is essential for earthquake early warning systems, which have the potential to alert nearby populations about the approach of potentially damaging seismic waves (e.g., Allen and Kanamori 2003; Kanamori 2005). In addition, minimizing the time required to estimate the extent and amplitude of ground shaking from an earthquake is necessary for rapid deployment of emergency personnel to affected areas. A dense array of seismometers can reduce the time needed to detect an event and provide higher resolution maps of ground accelerations across a region. Quake-Catcher Network (QCN) is a new type of seismic network that implements distributed/volunteer computing combined with micro-electro-mechanical systems (MEMS) accelerometers to record earthquakes (Cochran, Lawrence, Christensen and Chung 2009; Cochran, Lawrence, Christensen and Jakka 2009). Almost any modern computer can become a seismic station provided it has Internet access and either an internal or external MEMS accelerometer. After the initial development costs, the QCN seismic data gathering system costs less than 1% of a traditional network, thus enabling very-high-density seismic monitoring at affordable cost levels. On 27 February 2010 an M 8.8 earthquake occurred on the subduction plate interface offshore of central Chile, with its epicenter approximately 335 km southwest of Santiago and 105 km northwest of Concepción (USGS 2010). The sole QCN accelerometer in Chile at the time, an external USB accelerometer connected to a desktop, recorded this event (see Figure 1). Although the sensor was not properly secured to the floor at the time of the earthquake, it was able to record more than 120 seconds of on-scale strong-motion shaking. Following the mainshock, a QCN Rapid Aftershock Mobilization Program (RAMP) was initialized in Chile and the dense network recorded a large number of aftershocks in and around the...