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R. A. Kerr

Publications and source records attributed to R. A. Kerr.

18 recordsLinked to original sources
USGS1989

New fault picture points toward San Francisco Bay area earthquakes

Recent earthquakes and a new way of looking at faults suggest that damaging earthquakes are closing in on the San Francisco area. Earthquakes Awareness Week 1989 in northern California started off with a bang on Monday, 3 April, when a magnitude 4.8 earthquake struck 15 kilometers northeast of San Jose. The relatively small shock-its primary damage was the shattering of an air-control tower window-got the immediate attention of three U.S Geological Survey seismologists in Menlo Park near San Francisco. David Oppenheimer, William Bakun, and Allan Lindh had forecast a nearby earthquake in a just completed report, and this, they thought, might be it.

California↗
USGS1989

Notes about the Armenia earthquake, 7 December 1988

The Earth's crust is a jigsaw of rigid plates like huge paving stones. According to the theory of plate tectonics, these lithosphere plates are constantly in motion, slowly realigning themselves with the passage of time. Ninety to niety-five percent of all earthquakes occur where the plates collide with each other. In Armenia, the Arabian plate abuts against the Eurasian (Europe-Asia) plate. As a result, the region has been plagued by sever earthquakes for thousands of years: an earthquake in 893 A.D. took an estimated 20,000 lives; another in 1667 took 80,000 lives. Whenever the plates moving beneath Armenia interlock, pressure builds. The stress increases, the pressure continues to climb and finally there is a fracture-a sudden release of energy we know as an earthquake.

Earthquakes & Volcanoes (USGS)↗
USGS1989

Taking the pulse of the San Andreas Fault

The ninth of January, 1989, was the 32nd anniversary of the great southern California earthquake of 1857. the latest research shows that, on average, at least part of the section of the San Andreas fault that broke then should break again this year. But the same research suggests that the fault's average behavior could be misleading. A newly refined dating of the past 10 San Andreas ruptures adjacent to Los Angeles reveals a previously unrecognized clustering of large earthquakes in bunches of two or three. If this pattern were to hold, Los Angeles would wait at least another 80 years for another jolt from there. But the San Andreas is not that easy to get around.

California↗
USGS1989

The Moon; twenty years later

The 20th anniversary of the first landing on the Moon occurred on July 21, 1989. The vast majority of the Moon rocks collected by the Apollo mission astronauts await further study in the continuing effort to unravel the origin and evolution of Earth's nearest neighbor. Not that the 382-kilogram treasure trove of lunar samples has been gathering dust in the Planetary Materials Laboratory at the Johnson Space Center in Houston. It is just that lunar scientists are being very sparing in their use of the rocks.

Earthquakes & Volcanoes (USGS)↗
USGS1989

Triumph of the Voyager mission

It had been a long, productive trip. Launched in 1977, the two Voyager spacecraft had visited three giant planets, a dozen major Moons, three ring systems with thousands of rings composed of a myriad of tiny Moonlets. The spacecraft had returned 5 trillion bits of data and over 100,000 photographs. The last encounter in our Solar System by Voyager 2 with Neptune was to be a spectacular finale to the 12-year drama.

Earthquakes & Volcanoes (USGS)↗
USGS1988

Forecasting California’s earthquakes

The first official earthquake forecast for California emphasizes the broad extent of the hazard and the uncertainties involved in predicting the next quakes. For the first time, researchers have reached to a consensus on the threat of large earthquakes to California, things look no worse for Los Angles than before. It still has about a 60 percent chance of being shaken by a large earthquake sometime during the next 30 years. But other heavily populated areas of California, such as San Bernardino and the East Bay area of San Francisco, are now getting their fair share of attention. The new consensus also points up the considerable uncertainties invloved in earthquake forecasting.

California↗
USGS1988

What is worse than the “big one”?

The Whittier Narrows California earthquake sequence (local magnitude, Ml=5.9 or 1 October, 1987), which caused over $358 million damage, indicates that assessments of earthquake hazards in Los Angeles metropolitan area may be underestimated. the sequence ruptured a previously unidentified thrust fault that may be part of a large system of thrust faults that extends across the entire east-west length of the northern margin of the Los Angeles basin. Peak horizontal accelerations from the main shock, which were measured at ground level and in structures, were as high as 0.6g (where g is acceleration of gravity at sea level) within 50 kilometers of the epicenter The first thought in the minds of many residents of the city of Whittier when the first shock hit them was "Is this the big one?" the San Andreas' once-in-150-years great shaker? It might as well have been for Whittier, which is 20 kilometers east of downtown Los Angeles. The ground shook harder there this month than it will when the big one does strike the distant San Andreas, which lies 50 kilometers on the other side of the mountains. And this was only a moderate, magnitude 6.1 shock. Earthquake of magnitude 7 and large 30 times more powerful, could rupture faults beneath the feet of Angelenos at any time. The loss of life and destruction could exceed that caused by the big one.

California↗
USGS1987

Lake Nyos was rigged for disaster

Studies suggest that magmatic gas seepage had turned Lake Nyos in Cameroon into a time bomb; evidence mounts against a volcanic trigger for last August's disaster.

Lake Nyos is a crater lake in the Northwest Region↗
USGS1984

Stalking the next Parkfield earthquake in Central California

Looking southeast from Middle Mountain toward Gold Hill, it is a subtle furrow in the grassy knolls of the Cholame Valley of California's Coast Range. To geophysicists, this 19-mile section of the San Andreas fault midway between San Francisco and Los Angeles is the most well understood, most intensely monitored fault in the world. As such, it is also the most likely place for American earthquake researchers to become earthquake predictors. The present understanding of the fault has already prompted speculations that the next moderate Parkfield earthquake will strike in early 1988, give or take a few years. Perhaps more importnat, the next rupture of the Parkfield section of the fault could get out of hand and create a much larger earthquake.

California↗
USGS1980

The Southern California uplift revisited

The earthquake that struck Livermore, east of San Francisco, on January 24 was the second moderate earthquake to have occurred in the San Francisco Bay area in 5 months. It raised familiar questions. Does this mean that the "Big One" is coming? Is the theater of heightened concern now in northern California.

California↗