Vertically Displaced Research Articles

Late Quaternary Activity of Hinagu Fault, West Central Kyushu

The Hinagu fault running nearly from NNE to SSW can be traced more than 40km long from Tanoura through Hinagu and Yatsushiro to the north of Mifune. The fault cut diagonally to the Usuki-Yatsushiro Tectonic Line which is westernmost continuation of Median Tectonic Line. At the southern part of the fault, the fault divides Kyushu mountains to the east and Yatsushiro plain to the west. The fault runs through the river terraces and the depositional surface of Aso pyroclastic flow, at the northern part of the fault.Recent activity of Hinagu fault is mainly characterized by right lateral movement and the horizontal displacement along the fault trace amounts 106 meters in maximum. The average rate of the horizontal displacement is estimated at 0.8 meters per 1, 000 years, judging from the 12 meters offset valley dissecting the Middle fan formed at about 15, 000 years ago. At the southern part of the trace, the Middle and Lower fans are vertically displaced by the fault. At the northern part of the fault, the fault trace arranges en echelon and displaces the depositional surface of Aso pyroclastic flow and the Lower river terraces, vertically. The average rate of vertical displacement is estimated at 0.5-0.7 meters per 1, 000 years.In Central Kyushu, the crustal movement with the directions of NNE-SSW and NE-SW is typically recognized at the Hinagu fault and Shigi trough which located at the northwest Amakusa Islands (CHIDA, 1976). The activity of recent right lateral faulting along the Hinagu fault agree with the formation of Shigi trough, in age. This agreement is considered as the activity of Ryukyu arc corresponded to the change of stress states during Late Quaternary period.

立川断層とその第四紀後期の運動

The Musashino Upland, a dissected fan of the Tama River in the western suburbs of Tokyo, is displaced by the Tachikawa fault, which runs in a NW-SE direction with long-continued flexure scarps.Using the tephrochronological method and data of water well logs, the author investigated geomorphic features and movement history of the fault in detail. It is thus revealed that the fault has displaced the terrace surfaces of various ages, including the Tc3 surface of 14, 000 years B.P. and the Holocene old stream channels (Fig. 1, Fig. 10). The Plio-Pleistocene sediments, buried under the Musashino Upland, have been vertically displaced about 70m at Hakonegasaki (Fig. 5, Fig. 6). This fault has only vertical displacement with no strike-slip component, and the upthrown side of the fault is northest. The long-term average slip-rate, derived from the displacement of terrace surfaces, is the largest in the central part of the fault and gradually decreases toward the both ends. The maximum average slip-rate is 36cm/1000 years.The total length of the fault is 21km. If examined in detail, it may be divided into two segments from discontinuity of the geomorphic expression and difference in the long-term slip-rate (Fig. 11). No sign of fault movement has been found from precise levelling across this fault for 40 years. So it is thought that fault movements had been recurred on this fault with large earthquakes in the late Quaternary period. The fault displacement in an earthquake, the earthquake magnitude, and its recurrence interval are estimated at about 1.8m, M. 7.1, and 5, 000 years, respectively.There are two types of surface deformations along the Tachikawa fault. One is a flexure scarp of 100-300 meters in width (Fig. 8). This flexure scarp is thought to have been formed by the existence of thick unconsolidated fluvial gravel deposits overlying the faulted Plio-Pleistocene sediments. The other is a broad undulation of a few kilometers in a half-wave length across the fault trace (Fig. 12). This undulation seems to reflect the elastic dislocation of the crust due to the movements of the Tachikawa fault.

Vertical displacement of membrane proteins mediated by changes in microviscosity.

Membrane proteins of intact human erythrocytes were labeled with two fluorescent sulfhydryl reagents. The tagged cells were then subjected to simultaneous liposome treatments for either depletion or enrichment of membrane cholesterol content. Cholesterol depletion, which reduces membrane microviscosity, was followed by a series of fluorescence changes all indicating masking of the membrane proteins. Conversely increasing the membrane microviscosity by cholesterol enrichment resulted in an appreciable increase of the protein exposure to the aqueous surrounding. These findings strongly suggest that membrane proteins may be vertically displaced upon changes in lipid fluidity, a mechanism that may play a significant role in modulation of antigens and receptors in vivo.