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The response of nonlinear hysteretic multistory buildings to random strong motion earthquakes is investigated by Monte Carlo method using a hybrid computer scheme. Digitally produced artificial earthquakes are applied to several different analog models of multistory structures and the corresponding responses are studied statistically. The effects of natural period, hysteretic model, and earthquake intensity are discussed.

In this paper, the authers have studied the characteristics of the seismic earth pressure and of the dynamic water pressure acting on quaywall.At first, the seismic earth pressure is discussed theoriticaly, regarding the backfill as the elastic media whose constants are expressed as a fanction of the depth.Next, it is made clear that the dynamic water pressure due to backfill's pore water can not be neglected for the seismic pressure theoretically. Making use of these results, the critical earthquake intensity for the base sliding of the gravity type quaywall is obtained and it is shown that the seismic damage in Japan can be well explained with this criterion.

Nevada earthquakes for the period from about 1852 to 1961 are tabulated on I.B.M. punch cards. During this period 1,173 events with Nevada epicenters were felt, 586 others with Richter magnitudes above 4.0 were recorded and were probably felt by some residents, and approximately 220 were reported in nonspecific terms (e.g. “several aftershocks were felt”). High seismicity of this region is indicated by the fact that on an equal-area basis, during the period 1934-1960, Nevada has had the highest incidence of earthquakes per unit area of any of the conterminous Western States. The seismic activity shows a distinct tendency, statistically inadequate, for a 20-year cycle of activity, with peaks at about 1852(?), 1872, 1894, 1916, 1932-1933, and 1954. The general increase in number of events reported each year correlates well with the increase in Nevada population, but is probably modified by the development of: increasingly sophisticated methods of recording, spacing of seismographic stations, more intensive earthquake investigations of the United States Coast and Geodetic Survey, and changing population density and distritution.A method is developed for correlating between Richter magnitude, earthquake intensity, and size of felt area. This permits estimation of earthquake magnitude for shocks that pre-date instrumental methods of recording.The areal distribution of the earthquake epicenters does not indicate a noticeable change in pattern during this brief historic period, except possible recent intensification of activity near Lake Mead. Seismic activity is concentrated in three zones: a Western Nevada-Eastern California Zone which includes the northern Sierra Nevada frontal faults, Fish Lake Valley-Furnace Creek-Death Valley fault systems and Walker Lane; a 118° Meridian Seismic Zone which contains most of the historic surface faults; and a weak Southern Nevada Transverse Zone that includes the Lake Mead activity.

The nature and use of the Modified Mercalli intensity scale is explained, and the degrees of the scale redefined in terms capable of direct application in New Zealand.

A procedure for finding a theoretical earthquake intensity is proposed, and the anomaly is defined as the difference between observed and theoretical intensities. Interpretation of the anomalies is discussed. Application of the method to an Azorean earthquake shows conspicuous negative anomalies, which appear to indicate the probable emplacement of magma chambers of the volcanic system formed by Fayal and Pico Islands.

In the leading European scientific weekly (Nature, Feb. 22, 1930, p. 292) we read that “the Riviera Earthquake (Feb. 23, 1887) was not one of great strength for only 640 persons were killed, while the area disturbed contained 219,000 square miles.”