DETERMINATION OF PREDOMINANT SITE PERIOD OF LOOSE TERRESTRIAL UNITS (CALICHE) WITH MICROTREMOR MEASUREMENTS

Abstract

The caliche profi les that have been observed in arid-semi arid climate regions can be described as terrestrial formations which are vertical succession and composed predominantly of calcium carbonate. At the top of the caliche profi le, there is hard pan leyer as a weak rock and soft pan layer characterized by loose soil is existed. Caliche is formed by the displacement and/or cementation of soil, rock, and weathered material, and is usually found in unsaturated zones. In the study area, consist of caliche units located in Adana. It is noteworthy that the caliches of Quaternary is widely crop out throughout the region, exhibited a fl at topography in the region locate at this unit. The paleosolic deposits in the Adana Basin, which is characterized by climate oscillations in the Pleistocene and surface waters rich in carbonate, following draining, capillarity and weathering, initially formed as a result of sedimentological and followed by pedological processes. Adana is located in the I. and II. degree seismic zone, where many earthquakes have been observed in historical and instrumental periods. It was found that the greatest structural damage sustained by the earthquakes that occurred in Adana especially in 1998, was seen in the buildings located on caliche ; it is believed that the damage caused to the buildings located on chalice can be attributed to the of morphologically distinct layers or horizons. This study determines the sediment amplifi cation characteristics and horizontal to vertical spectral ratio (H/V) within the borders. Accordingly, to demonstrate H/V between the hard pan and the soft pan horizon of the caliche, 24 microtremor measurements were performed on locatio ns with soft pan, on locations with no hard pan, and on locations where the profi le directly begins with the soft pan.