A simulator for testing the on-site EEWS. It pROVides real-time warning to places closer to the epicenter.

Pacific-Rim earthquake belt, the so-called “Ring of Fire,” which is an extremely active tectonic region with seismic activities among the highest in the world. According to the record that has been taken since 1736, catastrophic earthquakes occurred in Taiwan every 15 to 20 years. Over the past century, earthquakes account for a loss of about 70 human lives and NT$30 billion (about US$1 billion) in physical damage annually. But the magnitude of recent economic loss and seismic damage aggravates as the nation undergoes profound economic growth and urbanization. The 921 earthquake, which occurred on 21 September 1999, alone caused damage included 2,415 deaths, 29 missing, 11,305 severely wounded, with 51,711 buildings completely destroyed, and 53,768 buildings severely damaged. It was the second-deadliest quake in recorded history in Taiwan, after the 1935 Hsinchu-Taichung earthquake.

In the face of seismic threats that so seriously impede Taiwan's national security, it is imperative for the country to construct a safe living environment for its people. And toward this end, the NARL’s National Center for Research on Earthquake Engineering (NCREE) is striving for collaborative, interdisciplinary research in the science and engineering of rapid earthquake detection and notification for the country.

When an earthquake occurs, the released energy travels through and around the earth with seismic waves as vibrations. The fastest kind of seismic wave is the primary waves (P waves), which are the first to travel outward. They are followed by the secondary or shear waves (S-waves); there is typically a one-second separation between the P- and S-waves for every 8 km traveled. The S-waves travel through the earth as a sequence of up-and-down vibrations perpendicular to the surface of the earth, thus cause stronger tremors. Most earthquake-induced damage results from these S-waves. The P waves, despite their small and nondestructive amplitude, carry the information of the earthquake size. In reference to historical data, an estimation of the earthquake size from the P wave pROVides information about the strength of shaking to be brought by the following S wave. Using the P wave information to estimate the S wave’s destructive strength is a basic concept of earthquake early warning. Most earthquake early warning systems (EEWS) developed so far are conceived as either “regional” (network-based) or “on-site” (stand-alone) systems. Regional EEWS consist of a broad-based seismic sensor network covering a portion or the entire area which is threatened by the quake's strike but relatively distant from the epicenter. On-site EEWS, on the other hand, contain the seismometers that are installed on-site to pROVide real-time warning to places closer to the epicenter.

Since 2008 the NARL-NCREE has been collaborating with the nation’s meteorological research and forecasting institution, the Central Weather Bureau, and the NARL’s two other centers—National Science and Technology Center for Disaster Reduction and National Center for High-performance Computing to develop the on-site EEWS. From this concerted effort, Taiwan's very first on-site EEWS that features built-in automatic disaster reduction functions has been recently unveiled. This smart earthquake disaster reduction system has been tried and pROVed via the earthquake simulation shaking table test.

The newly developed on-site EEWS is capable of sending out warnings within three seconds on the arrival of P-waves. If expecting violent S-waves are to arrive, the system will additionally activate necessary prevention measures up to over ten seconds in advance, depending on the destined location and its distance from the epicenter. The new system, with 80% accuracy rate in preliminary testing, could be linked to the places and institutions that need the seismic information—factories, hospitals, schools, trains, high-rise buildings, power plants, construction sites, etc. And the system can be programmed to automatically warning school kids to duck and take cover, stop the elevator at the nearest floor, shut off water and gas valves, turn on back-up generators for hospitals, etc. Currently, demonstration stations, costing more than NT$10 million, of the on-site EEWS have been installed at Fanghe Junior High School in Taipei City, Yilan Elementary School in Yilan County, and National Chung Cheng University in Chiayi County, as well as SECOM Co., Ltd., the largest security management company in Asia, for long-term on-site testing. The ultimate construction of a smart earthquake disaster reduction environment nation-wide will be established, and this investment certainly will pay off.