Most instruments used in seismological practice to record ground motion are pendulum seismographs, velocigraphs, or accelerographs. In most cases it is assumed that seismic instruments are only sensitive to the translational motion of the instrument’s base. In this study the full equation of pendulum motion, including the inputs of rotations and tilts, is considered. It is shown that tilting th...

The validity of the adiabatic assumption used in estimating vertical motion is examined by comparing the relative contributions due to adiabatic processes with the diabatic process of infrared cooling. Radiometersonde data are used to prepare vertical profiles of the adiabatic and infrared components of the vertical motion. These data are first filtered to reduce the effect of random errors. Al...

Sloshing is a well-known phenomenon in liquid storage tanks subjected to base or body motions. In recent years the use of multiple vertical baffles for reducing the sloshing effects in tanks subjected to earthquake has not been taken into consideration so much. On the other hand, although some of the existing computer programs are capable to model sloshing phenomenon with acceptable accuracy, t...

The equations for the earthquake forces on a rigid dam with an inclined upstream face of constant slope are solved exactly by two-dimensional potential-flow theory. The distribution of the hydrodynamic pressure along the upstream face and the total horizontal, vertical and normal loads on the dam are computed from the integral solutions. The results obtained from the exact theory are compared w...

Zhan et al. (2014a) reported supershear rupture during the Mw 6.7 aftershock of the 2013 Mw 8.3 Sea of Okhotsk deep earthquake, relying heavily on the regional station PET, which played a critical role in constraining the vertical rupture dimension and rupture speed. Here we include fivemore regional stations and find that the durations of the source time functions derived from these stations a...

zipper braced frames are an innovative bracing system for steel structures. conventional inverted-v-braced frames exhibit a design problem arising from the unbalanced vertical force generated by the lower story braces when one of them buckles. this adverse effect can be mitigated by adding zipper columns or vertical members connecting the intersection points of the braces above the first floor....

In this paper, a methodology is presented for optimum shape design of double-layer grids subject to gravity and earthquake loadings. The design variables are the number of divisions in two directions, the height between two layers and the cross-sectional areas of the structural elements. The objective function is the weight of the structure and the design constraints are some limitations on str...

[1] Many volcanic earthquakes large enough to be detected globally have anomalous focal mechanisms and frequency content. In a previous study, we examined the relationship between active volcanism and the occurrence of a specific type of shallow, non-double-couple earthquake. We identified 101 earthquakes with vertical compensated-linear-vector-dipole (vertical-CLVD) focal mechanisms that took ...

in the form of passive seismic methods, broadband seismometers have been used in hydrocarbon exploration. the frequency bandwidth typically studied is in the range of 1–6 hz. the observations on low frequency band of microtremors are used to calculate the spectral ratio of vertical and horizontal components (v/h) and power spectral density (psd). attributes based on the v/h ratio and the psd ha...

The September 21, 1999, Mw 7.6 Chichi earthquake destroyed several thousand buildings and caused more than 2000 fatalities in central Taiwan. The earthquake occurred along the Chelungpu fault, a thrust fault on the western flank of the Taiwan fold-andthrust belt. The surface rupture was more than 90 km long, and vertical displacements ranged from 3 to 8 m. Although pre-existing scarps were iden...