Executive Summary

 Taiwan is located in an active part of the Circum-Pacific seismic belt. Due to intense collision between the Philippine Sea and Eurasian plates, Taiwan experienced many disastrous earthquakes in the past. The 1999 Chi-Chi earthquake, which caused loss of more than 2,500 lives and collapse of more than 100,000 household dwelling units, was only the latest case. The incessant plate collision means that we will inevitably face earthquake hazards in the future. Unfortunately, occurrence of earthquakes still cannot be forecast, much of this is due to lack of predictive capability. The problem of earthquake prediction has been under intensive investigation for nearly forty years in Japan, China, and the U.S. Yet relatively little progress is made thus far. Our frustration over the surprising difficulty of earthquake prediction problem has recently led to a serious debate within the seismological community on predictability of earthquakes. Some people argued that earthquakes are inherently unpredictable. Yet others believe that earthquake prediction is possible. They maintain that our present inability to predict earthquakes is partly due to the inherent characteristics of earthquakes and partly to an incomplete understanding of the earthquake process. At the heart of the debate is the question on whether there are recognizable precursors of earthquakes? What could be precursors of impending earthquakes? A multitude have been suggested, but it is not clear which, if any, may become reliable. Recently, three major new developments encourage us to propose the present project. First, clear changes in geomagnetic total intensity were observed at Liyutan Station at least one month before and after the 1999 Chi-Chi earthquake. This station was near the northern end of the Chelungpu fault that caused the earthquake. The second major new development prompting us to formulate the present project is the observation of clear electromagnetic precursors in the ionosphere by ionosondes and GPS data. The third major new development is the physical process recently proposed to explain the electromagnetic signals associated with earthquakes which were observed both on ground and in the ionosphere. According to this process, igneous rocks contain positive hole pairs (PHP), i.e. dormant electronic charge carriers. The PHP can be activated by microfracturing and/or dislocation movement. Upon activation, the PHP release highly mobile charge carriers in form of positive holes. Positive holes are defect electrons in the oxygen sublattice of minerals that can conduct through rocks. Once generated these charges spread out of the source volume. Understanding these positive hole charge carriers and their manifestation enables us to re-evaluate electrical and magnetic phenomena associated with earthquake activities.    Given the above developments and taking into account the strength of our research team we decide to undertake an overall project called ‘Research on Seismo-Electromagnetic Precursors of Earthquakes’. It consists of five inter-related sub-projects covering the following subjects:: Sub-project I. A Study of Earthquake Precursors--Seismological variations, Sub-project II. A Study of Earthquake Precursors -- Variations of the Geomagnetic and Gravity Fields, Sub-project III. A Study of Earthquake Precursors: Radar Interferometry for Detection of Surface Deformation, Sub-project IV. A Study of Earthquake Precursors--Ionosospheric Variations, and Sub-project V. AsStatistical Study of Electromagnetic Precursors of Earthquakes. In the process of conducting these sub-projects, we shall develop close international cooperation with the following groups: Sub-project I: We will have close cooperation with Prof. Crampin group at British Geological Survey. This group is the first group to observe possible shear-wave splitting as earthquake precursor. We will also have corporation with Prof. L. Teng at USC for his experience on anisotropy and P-wave variation studies. Corporation with the USGS and other institutions are also possible through conferences and workshops. Sub-project II: Studies of the geomagnetic field intensity on ground will have close collaboration with Japanese and Mainland Chinese groups. Attendance of international conferences will also provide opportunities for international exchange and collaboration on this subject. Sub-project III: Precursory vertical changes in ground surface by INSAR will look for collaboration with Japanese and US groups to have close link with GPS observations. Sub-project IV: Studies on precursory ionospheric changes have long  collaboration with Dr. Freund at SETI Institute, NASA, Russian groups and Japanese scientists at Kyoto University. Recent results from studies on this subject have been published in journals and presented in several conferences and attracted a lot of attention. Sub-project V: Statistical treatments of electromagnetic precursors of earthquakes will try to have discussion and collaboration with other experienced groups on earthquake statistical studies, such as the group in USGS and New Zealand. Attending related international conferences will provide other opportunities for discussion and possible international collaboration. We expect to obtain significant results from execution of above five sub-projects, as summarized below: Sub-project I: We will seek for all the possible seismological precursors through observations of P-wave velocity and spectral variations, change of b-value and temporal and spatial variations of shear-wave splitting. The correlations among these observations will be examined. The seismological observations will, then, be combined with other non-seismological observations by other sub-projects to find the possibility on earthquake precursors and to look for possible physical mechanisms of these observations. We expect findings from seismological and non-seismological precursors studies will be leading results in this related field.  Sub-project II: The observations on geomagnetic field intensity on ground will be the most complete observation of the magnetic field in Taiwan. Sub-project III: Vertical changes in ground surface by INSAR is a frontier field in the earthquake precursor studies. INSAR has been recognized as a powerful tool of detecting ground deformation. On the basis of the powerful tool, we are looking for possible correlation of the vertical ground deformation with larger earthquakes. In this sub-project, the use of satellite thermal infrared data also will be applied to investigate possible surface and near surface temperature changes before a earthquake.  Sub-project IV: Our recent study on precursory changes in ionosphere is one of the most complete studies in this field so far. Through cross-correlation among the sub-projects, we will seek for the possibility of using the ionosphere observation as earthquake precursors and look for the possible physical mechanisms behind the observations. Sub-project V: The statistical treatment of electromagnetic precursors of earthquakes is still a new experience to us. We will apply our knowledge on statistics to all related observations (seismological, non-seismological) and look for possible correlation among results from the sub-projects. Eventually, we will try to correlate the observed precursors with existing earthquake formation models to lay foundation for future earthquake prediction.