Seismic anisotropy is an efficient way to investigate the deformation field within the upper mantle. In the framework of rigid tectonic plates, we make use of recent tomographic models of azimuthal anisotropy for deriving the best rotation pole of the Pacific plate in the uppermost 200km of the mantle. It is found to be in good agreement with current plate motion (NUVEL1, HS3 and NNR). However,...

This paper reports on the damage of Wushi bridge in a recent Taiwan 921 earthquake. Damage to Wushi bridge appeared in the superstructure, the substructure and the approaches. Typical types of damage are discussed and illustrated in this paper. A review of the bridge design specifications in Taiwan is also presented to give the background on the seismic design of Taiwan highway bridges.

Pletser et al. performed a seismic-refraction survey on Devon Island with the goal of assessing the feasibility of astronauts carrying out such operations on Mars to detect subsurface water. We demonstrate that the seismic analysis is fundamentally flawed. The survey performed in this test will likely bear little resemblance to future crewed geophysical surface operations, and better methods ex...

The period of vibration is a fundamental parameter in the force-based design of structures as this parameter defines the spectral acceleration and thus the base shear force to which the building should be designed. This paper takes a critical look at the way in which seismic design codes around the world have allowed the designer to estimate the period of vibration for use in both linear static...

Masonry structures are complex systems that require a thorough and detailed knowledge and information regarding their behaviour under seismic excitations. Appropriate modelling of a masonry structure is a prerequisite for a reliable earthquake resistant design or assessment. However, modelling a real structure to a robust quantitative (mathematical) representation is a very difficult, complex a...

This paper summarizes the results of a comprehensive study carried out to assess the seismic response of a 59-span bridge, considering Soil-Structure Interaction (SSI). The bridge was built in the early seventies at a distance of about 5 km from a major fault. The methodology adopted to idealize the bridge and its foundation system for elastic and inelastic analysis is briefly described. The SS...

We discuss three approaches to seismic interferometry and compare their underlying assumptions. In the first approach the reflection response is reconstructed by cross-correlating the responses of many uncorrelated noise sources. In the second approach a depth image is obtained from the response of a single source, recorded by many receivers. In the third approach the Green’s function is recons...

Time-lapse (4D) seismic data sets have proven to be extremely useful for reservoir monitoring. Seismic-derived impedance estimates are commonly used as a 4D attribute to constrain updates to reservoir fluid flow models. However, 4D seismic estimates of P-wave impedance can contain significant errors associated with the effects of seismic noise and the inherent instability of inverse methods. Th...

Most of the existing seismic design codes are based on the empirical knowledge accumulated through systematic earthquake damage data collection and their analysis. Required levels of protection and seismic design forces gradually are increased after each series of catastrophic earthquakes particularly in developed countries. Many efforts have been made through experimental and analytical studie...