We analyze Bouguer anomalies in/around the focal region of the 2016 Kumamoto earthquake to examine features, such as continuity, segmentation and faulting type, of the active fault zones related to the earthquake. Several derivatives and structural parameters calculated from a gravity gradient tensor are applied to highlight the features. First horizontal and vertical derivatives, as well as a ...

[1] We systematically investigate the velocity contrast along the Calaveras fault that ruptured during the 1984 Morgan Hill earthquake using fault zone head waves (FZHW) that refract along the fault interface. We stack waveforms in 353 sets of repeating clusters, and align the peaks or troughs of the direct P waves assuming rightlateral strike-slip focal mechanisms. The obtained velocity contra...

1. Location map of selected fault-controlled valleys in western Idaho and northeastern Oregon 3 2. Plot of all scarp height and slope angle values obtained in this study 5 3. Map of sackung features, vegetation lineaments, and landslide headscarps on West Mountain 6 4. Map of Meadows Valley, showing approximate trace of Meadows Valley fault zone 8 5. Surficial geologic map of the north end of M...

We have investigated gravity anomalies around the Niigata plain, which is a sedimentary basin in central Japan bounded by mountains, to examine the continuity of subsurface fault structures of a large fault zone—the eastern boundary fault zone of the Niigata plain (EBFZNP). The features of the Bouguer anomaly and its first horizontal and vertical derivatives clearly illustrate the EBFZNP. The s...

the nnw-trending dena fault, with 140 km length, cuts the major structures of zagros fold-thrust belt in borujen region. the fault has divided the region in two zones, in which different structural, andmorphological features as well assedimentation and seismtectonic characteristics have developed. this study presents a new interpretation for the kinematics of dena fault based on field evidence....

Triaxial experiments show that samples of fault gouge deform distinctly differently than those from the adjacent fault damage zone (e.g., Chester and Logan, 1986). Rock samples in the damage zone follow a characteristic elastic-brittle behavior, whereas fault gouge readily compacts and deforms in a more ductile manner. In order to explain the apparent weakness of large plate bounding faults suc...

Introduction: Quaternary basalts are one of the last signs of magmatism in Iran, some of which are related to deep fractures and active faults in the Quaternary. Quaternary basalts of Tabas are very important due to their high expansion and location in eastern Iran, and are located 140 km south east of Tabas city and according to the proposed divisions are part of the Lut zone. The aim of this...

Earthquake dynamics are strongly affected by fault zone structure and fault surface geometry. Here we investigate the interplay of bulk deformation and surface topography using detailed structural analysis of a fault zone near Klamath Falls, Oregon combined with LiDAR measurements of the fault surface. We find that the fault zone has a layered damage architecture. Slip primarily occurs inside a...

[1] The Uganik Thrust is a fossil out-of-sequence thrust fault which was active over a period of 3 Ma during the early Tertiary until activity ceased with the subduction of the Kula-Farallon spreading ridge at 57 Ma. During this period the fault experienced at least 1 km of throw and developed a strongly asymmetric damage zone. The brittle damage zone in the footwall of the fault acted as a con...