We have performed experiments on the laboratory scale to image seismic wavefronts of compressional waves that are guided between parallel fractures. The wavefronts are detected using water-coupled 1MHz piezoelectric transducers. The stiffness of the fractures is controlled by applying radial stress in a hydraulic stress apparatus that leaves the observation face of the fractured sample open to ...

A symmetric-Galerkin boundary element framework for fracture analysis with frictional contact (crack friction) on the crack surfaces is presented. The algorithm employs a continuous interpolation on the crack surface (utilizing quadratic boundary elements) and enables the determination of two important quantities for the problem, namely the local normal tractions and sliding displacements on th...

The problem of the unsteady perturbed two-dimensional flow at low Mach number of a viscous compressible fluid is studied taking the relation between the stress and deformation rates tensors that was obtained and applied in [1] and [3]. It is shown that the system of equations describing the phenomenon is totally hyperbolic and therefore the perturbations in any point P of the field are propagat...

We developed a kinematic earthquake cycle model applicable to transform fault zones, subduction zones, and collision zones on the basis of elastic dislocation theory. The crustal deformation associated with the periodic occurrence of interplate earthquakes is generally given by the superposition of viscoelastic responses to steady slip on the whole plate boundary, steady back slip on the seismi...

Interfaces in elastic media need not be in welded contact. For instance, fractures allow a small amount of slip to occur along their surfaces during the passage of a seismic wave. By slip, we mean that the displacement across the interface can be discontinuous. Reflection and transmission of plane waves in this case are frequency dependent. Previous numerical studies have chosen the finite-diff...

The mission of Wageningen UR (University & Research centre) is ‘To explore the potential of nature to improve the quality of life’. Within Wageningen UR, nine specialised research institutes of the DLO Foundation have joined forces with Wageningen University to help answer the most important questions in the domain of healthy food and living environment. With approximately 30 locations, 6,000 m...

This contribution examines discontinuities in DG. Discontinuities are addressed in terms of catenae and rising. The catena is defined as A WORD OR A COMBINATION OF WORDS THAT IS CONTINUOUS WITH RESPECT TO DOMINANCE. The definition identifies any tree or subtree of a tree as a catena. Rising occurs when a governor fails to dominate one (or more) of its governees. Two sorts of rising are distingu...

It is well-known that the solution for a straight dislocation in an infinite medium does not depend on the cut along which the displacement discontinuity is imposed. This is also true for a semi-infinite medium, or any simply-connected region. The stress and strain fields, energy and dislocation forces are the same regardless of the cut. Only displacements differ in the region between the two c...

A numerical method is presented for stability analysis of cable–bar structures. An optimization problem is formulated to find the minimum value of the incremental total potential energy that depends on the direction of the incremental displacements. The penalty method with slack variables is used for representing the discontinuity in member stiffness. The tangent stiffness matrix is shifted to ...

It has long been believed that trans-Alfvénic shock waves (TASWs), at which the flow velocity passes over the Alfvén velocity, cannot exist in the real world. Since a stationary trans-Alfvénic shock transition was obtained in a numerical simulation [1], this conventional view point was replaced by an opposite view point. The overall claim was that there is no principal difference between TASWs ...