We present a source model for the beginning of earthquakes based on the Griffith's fracture criterion. The initial state is a critical state of pre-existing circular fault, which is on the verge of instability. After the onset of instability, the fault grows with a progressively increasing rupture speed, satisfying the condition of fracture energy balance at the crack tip. We investigate the di...

We present a rupture model of the Hector Mine earthquake (M 7.1), determined from the joint inversion of strong-motion records, P and SH teleseismic body waves, Global Positioning System (GPS) displacement vectors, and measured surface offset. We solve for variable local slip, rake angle, rise time, and rupture velocity of a finite-fault model involving multiple segments. The inversion methodol...

the nw-se trending zagros fold and thrust belt extends for about 1,800 km from a location some 300 km se of the east anatolian fault in ne turkey to the strait of hormuz where the north-south trending zendan-minab-palami fault system (zmp) separates the zagros belt from the makran accretionary prism. the ne limit of the zagros belt is marked by the main zagros reverse fault which is rotated abo...

Based on the recent high-resolution laboratory experiments on propagating shear rupture, the constitutive law that governs shear rupture processes is discussed in view of the physical principles and constraints, and a specific constitutive law is proposed for shear rupture. It is demonstrated that nonuniform distributions of the constitutive law parameters on the fault are necessary for creatin...

New geologic mapping, morphologic fault scarp modeling, and geomorphic metrics in the Red Rock Valley, southwestern Montana, help characterize the Quaternary history of the virtually unstudied Monument Hill fault and tectonics of the youthful and seismically active Red Rock graben. Two generations of Pleistocene surface ruptures are preserved along the Monument Hill fault. Similarity in rupture...

At 00:43 UTC on 27 July 2022, a 15-km deep major earthquake with magnitude (M w ) 7.0 struck Northwestern Luzon, Philippines. The strongest ground shaking felt was at PHIVOLCS Earthquake Intensity Scale (PEIS) VII (destructive), equivalent to Modified Mercalli (MMI) VII, in Abra and along the coastal areas of Ilocos Sur. More than thousand landslides, rockfalls tension cracks were mapped, near ...

[1] We report on laboratory experiments which investigate interactions between aseismic slip, stress changes, and seismicity on a critically stressed fault during the nucleation of stick-slip instability. We monitor quasi-static and dynamic changes in local shear stress and fault slip with arrays of gages deployed along a simulated strike-slip fault (2m long and 0.4m deep) in a saw cut sample o...

Earthquake-related fault slip in the upper hundreds of meters of Earth's surface has remained largely unstudied because of challenges measuring deformation in the near field of a fault rupture. We analyze centimeter-scale accuracy mobile laser scanning (MLS) data of deformed vine rows within ±300 m of the principal surface expression of the M (magnitude) 6.0 2014 South Napa earthquake. Rather t...

to assess seismic hazard, it is essential to estimate the potential seismicity, particularly estimation of size of the largest earthquake that can be identified by a distinct fault or earthquake source. one of the methods applied to estimate magnitude of earthquake is use of empirical relationships between magnitude and fault parameters. fault parameters for the earthquakes from early instrumen...