A set of time-synchronized strong-motion accelerograms, obtained on the San Juan Bautista 156/101 Separation Bridge in California during the 6 August 1979 Coyote Lake earthquake (M, = 5.9), are used to study the spatial variation of ground motion at the bridge site, including traveling wave effects and the influence of multiple-support excitation. Analysis of the ground motion recorded at the b...

• Inner core differential rotation is highly time-varying during 1991–2017. was nearly locked to mantle before 2001 and after 2003. experienced a burst of 2001–2003. The may have excited the six-year oscillation in length-of-day. nature any between Earth's inner important for understanding magnetic field intradecadal variations length-of-day; however, consensus on existence rate still lacking 2...

This work is on the influence of rotational component earthquake excitations to response steel structures. In most studies, seismic input being modeled only using translational ground acceleration, while one ignored. was due observation that had minimal effect low-rise buildings. Hence, accelerometers used would not measure it, leading a lack records. Nowadays, technology provides such instrume...

Ground motion record selection methodologies are commonly developed to ensure that the input excitation used in response history analyses embodies essential conditions such as spectral compatibility, hazard and intensity measure consistency, seismological site-specific criteria, always performing a computationally efficient manner. A methodology utilizing genetic algorithms is revisited here, e...

An M L = 3.5 earthquake near Santa Maria, California, was recorded by the Southern California Seismic Network and a TERRAscope station at Santa Barbara (SBC) on 31 January 1991. The waveform of this event is dominated by 2to 5-sec waves, and is different from that of ordinary events with similar size. Inquiries into operations in several oil fields in the area revealed that hydro-fracturing at ...