Search for hidden fracture zones from dense gravity survey and remote sensing

(1) 2004年11月，在我们的新重力数据的基础上，结合日本西南重力研究组的重力数据库，发表了《日本列岛重力异常地图集：日本西南部和中部》（编辑：Yamamoto， A.和Shichi， R.）。(2)利用名古屋市及其周边1328次重力测量数据，绘制了新的重力异常图。重力异常资料结合钻孔和地面地质资料表明，滨和岛-松田断裂和松田-日新断裂前第三纪基底垂直位移分别约为550m和350m。(3)通过对岐阜北部宫宫盆地地区的密集重力测量、地质调查和地貌分析，认为宫宫盆地为北东-西南平行的宫宫断裂和依纳科断裂的右旋拉分盆地。(4)对阿特拉断裂带花岗岩进行了详细的裂缝填图和地球化学分析，发现阿特拉断裂带断裂对主断裂面250m范围内花岗岩的影响较为明显。

(1) On the basis of our new gravity data together with the gravity database of Gravity Research Group of Southwest Japan, "Gravity Anomaly Atlas of the Japanese Islands : South-West and Central Japan" (editors : Yamamoto, A. and Shichi, R.) was published in November 2004.(2) A new gravity anomaly map was drawn from a total of 1328 new gravity measurements in Nagoya City and its environs. The gravity anomaly data combined with bore-hole and surface geology data show that the vertical displacement of pre-Tertiary basements of the Biwajima-Atsuta Fault and the Atsuta-Nisshin Fault is approximately 550m and 350m, respectively.(3) Judging from a dense gravity survey, geological investigation and lineament analysis of the Miya basin area in northern Gifu Prefecture, the Miya basin was formed as a pull-apart basin by right-lateral movements of the Miya-toge and Enako Faults running parallel in NE-SW trend.(4) A detailed fracture mapping and geochemical analysis of granitic rocks in the Atera fault zone reveal that the influence of fracturing of the Atera Fault on the granitic rocks is prominent within 250m from the main fault plane.