Research in faulted archaeological site

研究了长野县野泽村和三重县北北镇高田平原西部边缘地区靠近活动断层的地貌发育和考古遗址变形。考古遗址对考察古地震活动性有重要意义：高田平原西缘地区至少在约100 ka以来就有单斜变形的积累。大冢遗址位于弯曲陡坡上。古坟时代的遗址虽然没有变形，但绳纹时代的地表可能受到断裂的影响。自中更新世以来，野泽村周围形成了几个河流阶地，没有发现活动断层的痕迹。位于较低阶地表面的Higashihara遗址显示向东倾斜约10度。最后一次断裂事件发生在ca.3ka，第二次断裂事件的年龄大于ca.5.5 ka。根据地貌发育和考古遗址的变形情况，可以考察过去断层事件的历史。北北多户Flexure位于三重县约罗山的西部边缘。断层在垂直方向上使年轻阶地面偏移1.5 ~ 1.8 m。地表没有日期，三是没有地震灾害的历史记录。然而，位于河流表面的上佐作遗址的表面向西南倾斜，显示了自6世纪以来北北-多户弯曲最近重新活跃的证据。根据考古遗址的变形情况，可以清楚地显示出过去断裂事件的时间。考虑到地貌学的发展，我们需要促进考古学家和构造地貌学家的合作工作。

Geomorphologic development and the deformation of archaeological site close to active fault are investigated in the western marginal area of Takada Plain, Nozawa Village, Nagano Prefecture and Hokusei Town, Mie Prefecture. Archaeological site is very useful to examine the paleoseismicity as follows:Monoclinal deformations have been accumulated at least since ca.100 ka in the western marginal area of Takada Plain. The Otsuka site is located in the flexural scarp. Although the ruins of Kofun age are not deformed, the surface of Jomon age is possibly affected by faulting. The Shinano (Chikuma) River has formed several fluvial terraces since the Middle Pleistocene around the Nozawa Village where no active fault trace is known. The Higashihara site located on the lower terrace surface shows the tilting about 10 degrees toward east. The latest faulting event occurred ca.3ka and the age of penultimate one is older than ca.5.5 ka. The history of past faulting events can be investigated on the basis of the geomorphologic development and the deformation of the archaeological site. Hokusei-Tado Flexure is located in the western fringe of the Yoro Mts, Mie Prefecture. The fault vertically offsets the young terrace surface by 1.5-1.8 m. The surface is not dated and three is no historic record of seismic disaster. However, the surface of Kamisosaku site on the fluvial surface is dipping toward SW displaying the evidence for recent reactivation of the Hokusei-Tado Flexure since 6th century.The timing of past faulting event is clearly shown by reference to the deformation of archaeological site. We need to prmote the co-operative works of archaeologist and tectonic geomorphologist taking the geomorphologic development into account.