北陸微小地震観測所の震源マップの概要について-約1万個の地震データのとりまとめ-

Abstract

More than 10, 000 earthquake data has been obtained since the telemeter observation systemwas set up at the Hokuriku Microearthquake Observatory in May 1976. Hypocenters arecalculated on a mini computer at the observatory and stored in a disk file, which provides uswith various seismicity maps and cross sections. Maps classified by magnitude show that theobservation system can detect almost all M>2 events occurring in the area shown by the routinemap.The hypocenters are determined accurate enough to compare them on the whole with mapsof other geophysical informations, such as the distribution of active faults or the Bouguer anom-alies. To study more detailed features of hypocenters, we have, however, to relocate them byparticular methods, e.g., the master event technique, or have even to reproduce high speed paperrecords from the analog data recorder.We have found a few deficiencies in the present way of hypocenter determination. Forexample, the stations used to locate the earthquakes in a certain area are not always the same.We are preparing to improve those deficiencies found through this study.