1984年8月7日日向灘地震に関連した宮崎地殻変動観測所における地殻変動と地震活動

Abstract

Large earthquake with magnitude 7.1 occurred on Aug. 7, 1984, in the Hyuganada eastoff Kyushu, where the seismic activities including earthquakes with magnitude between 7.0 and7.6 have been excited with a recurrence time of about 30 years. Seismic activities and crustalmovement before and after this earthquake are examined by using data observed at the MiyazakiCrustal Movement Observatory with epicentral distance of 93 km. Seismic activities around theHyuganada region were very low before the earthquake. The precursory crustal deformationsjust prior to this earthquake were not found for all components of extensometers, tiltmeters anddistance measurement.