Some Investigations of Shallow Earthquakes (I)

Worldwide Doublets of Large Shallow Earthquakes

We investigated all the pairs of Mw >-7.5 shallow earthquakes in the Harvard catalog that occurred at a centroid distance of less than 100 km. We showed that most of these pairs have similar focal mechanisms. Because these earthquakes generally should have focal regions in excess of 100 km diameter, their rupture zones apparently intersect. For all these pairs, the time interval is significantl...

Dynamic triggering of shallow earthquakes near Beijing, China

S U M M A R Y We perform a comprehensive analysis of dynamic triggering around the Babaoshan and Huangzhuang-Gaoliying faults near Beijing, China. The triggered earthquakes are identified as impulsive seismic arrivals with clearP and S waves in 5 Hz high-pass-filtered three-component velocity seismograms during the passage of large amplitude body and surface waves of large teleseismic earthquak...

Design of Shallow and Deep Foundations for Earthquakes

Foundations may undergo severe distress during an earthquake. One such example of foundation failure involving toppling of apartment blocks due to liquefaction during the 1964 Niigata Earthquake is presented in Figure 1. Earthquake effects on shallow and deep foundations are accounted for by designing them structurally to provide necessary strength and ensure serviceability. Strength considerat...

Magnitudes of Great Shallow Earthquakes from 1904 to 1952

The "revised magnitudes", M, converted from Gutenberg's unified magnitude, m, and listed by Richter (1958) and Duda (1965) are systematically higher than the magnitudes listed by Gutenberg and Richter (1954) in Seismicity of the Earth. This difference is examined on the basis of Gutenberg and Richter's unpublished original worksheets for $eismicity of the Earth. It is concluded that (1) the mag...

Fluid pressure variations and prediction of shallow earthquakes.