Earthquakes, Faulting, and Nuclear Reactors

Most of the recent controversy concerning seismic hazards to proposed nuclear facilities in California has centered not on the usual problems of earthquake-resistant design but instead on the possible hazards associated with ground displacements by faulting through the foundation of a nuclear plant. In addition, there has been much difference of opinion as to the maximum credible earthquake that should be specified for any given area

Earthquake prediction — 1982 overview

Short-term earthquake prediction represents a more difficult scientific problem than most of us thought 5 yr ago when the National Earthquake Hazards Reduction Program commenced, and our progress has not been as rapid as initially hoped. At this point, reasons can be cited for both encouragement and discouragement. Despite slow progress, the goal of short-term prediction remains realistic, and research should continue vigorously, albeit with some changes in scientific strategy. In contrast, progress in long-term prediction and hazard evaluation has been far more rapid than initially envisaged

Charles F. Richter: A personal tribute

With the death of Charles Richter in 1985, the seismological community lost a renowned colleague, and many of us lost a close friend and advisor. Charles was born on a farm in Ohio in 1900, received his A.B. from Stanford in 1920, and his Ph.D. from Caltech in 1928. Virtually his entire professional career was spent at the Seismological Laboratory in Pasadena, first as an employee of the Carnegie Institution of Washington and later as a Caltech faculty member. Following his retirement from Caltech in 1970, he was active for several years in the consulting firm of Lindvall, Richter, and Associates. His wife, Lillian, died in 1972, and they had no children. Richter served as President of the Seismological Society of America from 1959 to 1960 and was the second recipient of its medal in 1977

Circum-Pacific faulting in the Philippines-Taiwan Region

Conflicting views of circum-Pacific tectonics have focused on the Philippines-Taiwan region, where there has been neither convincing documentation nor general agreement on the importance of transcurrent (strike-slip) faulting or the possible sense of regional horizontal displacement. Structural and physiographic features of the 1200-km-long Philippine fault zone are fully as spectacular as those of the better-known San Andreas and Alpine faults, and current activity is indicated by many localities in which scarps cut Recent gravels. Predominance of horizontal over vertical displacements is indicated by linearity of the fault trace, failure of one side to be consistently higher than the other, disregard for gross physiography, and scissoring of individual scarps within the zone. Consistent stream offsets on Luzon, Masbate, and Leyte demonstrate unequivocally that the sense of Recent displacement has been uniformly sinistral (left-handed). The Philippine fault has no obvious geologic relationship to active volcanoes, but the parallelism and proximity of the fault to the Mindanao trench suggest a close causal relationship. The remarkable Longitudinal Valley of eastern Taiwan represents another great transcurrent fault parallel to the western Pacific rim, and ground displacements during historic earthquakes indicate a sinistral sense of displacement here as well as in the adjacent Philippines. This study does not support the hypothesis of counterclockwise rotation of the Pacific basin, but more important is the further documentation of the predominance of transcurrent faulting in active circum-Pacific orogenic areas. These results reinforce earlier field studies in Alaska, California, Chile, and New Zealand, as well as emphasizing the geological reasonability of the results of seismic fault-plane solutions indicating the world-wide predominance of transcurrent movements

The San Andreas Fault

Every earthquake on the San Andreas fault, no matter how small, seems to renew public interest in this intriguing geologic feature. The recent San Francisco earthquake of March 22nd was no exception, although the press reports might well have left readers in doubt as to the true significance of this earthquake in the over-all history of the fault. Is it true, as stated in one publication, that this earthquake represents the San Andreas's "periodic shrug"? What is the San Andreas fault, and what do geologists and seismologists expect in the way of future activity

Earthquakes and Mountains Around the Pacific

Even after a century of intensive study, the problem of the origin of mountain systems remains as possibly the greatest enigma of the earth sciences. Specifically, what is the origin of mountain- building forces, and how are these forces manifested in the crustal rocks of the earth's surface

Quaternary Geology – An Essential Clue to Evaluating Seismicity

The geologic record, particularly that of the late Quaternary period, is a far more valuable tool in estimating seismicity and associated seismic hazard than has generally been recognized. This is simply because, by looking into the recent geologic past, the geologist is able to overcome many of the statistical inadequacies of the relatively short instrumental and historic records. These shortcomings are best illustrated in those parts of the world with the longest historic records of earthquakes—2000 years for Japan and the Middle East and 3000 years for China—where surprising variations in both the rates of recurrence and places of recurrence are evident. These long records show that earthquakes are by no means uniform in space and time, at least over intervals of only 1000 or 2000 years

The San Andreas Fault: Its significance in California's Past and Future

Every earthquake on, or close to, the San Andreas fault, no matter how small, seems to renew interest in this intriguing geologic feature. Is it true, as the newspapers usually say, that these earthquakes represent the San Andreas's "periodic shrug"? What is the San Andreas fault, and what do geologists and seismologists expect in the way of future activity