Earthquake early warning systems aim to protect life and property from destructive shaking by warning people and systems to take action in advance. Sensor and monitoring technology together with earthquake engineering allow prediction of intense shaking, seconds before arriving to the site. Algorithms developed by scientists use early waveform observations (such as peak amplitudes) to predict later shaking events. Due to velocity differences between p-waves and s-waves it is possible to obtain information about an ongoing seismic event with initial p-wave arrivals before arrival of damaging seismic waves. Warning time depend on distance from the epicenter, path and site conditions and computation time of the algorithms. Depending on this warning time, blind zones occur. There is a trade-off between the accuracy of predictions and warning time provided, however recent advances in technology and algorithms allow accurate warnings with only around 3 seconds of blind zone.

The earthquake early warning (EEW) research group at the National Taiwan University (NTU) and the San Lien Technology Corp. (http://www.sanlien.com.tw) have been developing a MEMS type of accelerometer (the “Palert” EEW device) specifically designed for onsite and front-detection EEW purposes. In addition to the physical properties of the MEMS accelerometer, the main advantage of the MEMS accelerometer comparing to the other seismometers is that it is a relatively very low-cost seismic sensor. We present the performances of the recently installed prototype EEW network at the eastern Taiwan region consisting of the Palert devices. The results of this prototype EEW system encourage the further implementations for the MEMS-type of seismometer in the EEW application. The Palert device has a high commercial potential owing to its low cost. The EEW system could be established in a relatively low budge and the Palert devices could be readily added to the existing seismic network to increase the density of the network. The prototype EEW system belongs to the front-detection type. Nevertheless, the Palert device also can be used in the on-site type, which the initial Pwave motion at a target site is used to predict the ground motions of the later S and surface waves at the same site.