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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 127 records · Page 7Linked to original sources
USGS1987

Picture windows of opportunity

We hate to say that we need a moderate earthquake every once in a while, but experience shows that it surely helps to sell all kinds of seismic safety programs It took the 933 Long Beach earthquake to get the Field Act passed in California requiring the strengthening of our public schools. It took the 197 San Fernando earthquake for Los Angeles to enact a retrofit ordinance requiring reinforcement of demolition of our 8,000 unreinforced masonry buildings, and the 1985 Mexico City earthquake to shorten its compliance period. It took the 1983 Coalinga earthquake to get the State of California to require the identification of unreinforced masonry buildings in risk areas throughout the state.

Earthquakes & Volcanoes (USGS)↗
USGS1993

Where lava meets the sea; Kilauea Volcano, Hawaii

Active volcanoes on the island of Hawai'i provide scientists with exceptional opportunities to observe volcanic phenomena at close range. Such an opportunity occurred on November 24, 1992, when geologists from the Hawaiian Volcano Observatory (HVO) witnessed spectacular explosive interactions between lava and seawater on the southeast coast of the island. As seawater invaded submarine conduits transporting milten lava, large steam explosions produced glowing fountains of lava that rose as high as 100m into the air and built a 7.5-m-high mound of volcanic ejecta called a littoral cone (see cover paragraphs). Seaside explosions of the type and magnitude of the event on November 24, 1992, are infrequent. the observation of this event represents a rare opportunity to enhance our understanding of the birth of littoral cones and the nature of explosive activity when lava enters the ocean.

Hawaii↗
USGS1992

Preliminary seismological results

On April 25 and April 26, 992, three earthquakes with magnitude (M) equal to or greater than 6.6 occurred near Cape Mendocino, California. the sequence began with a relatively shallow earthquake (M=7.1) on Saturday, April 25, at 11:06 a.m. local time. The two most most powerful aftershocks has magnitudes of 6.6 and 6.7. They occurred at 00:41 a.m. and 4:18 a.m. local times, respectively, on Sunday, April 26. The mainshock had a focal depth of about 10 km and the hypocenters of the strong afterschokcs were about 20 km deep. During the next three weeks, approximately 1500 aftershocks were recorded by the seismographic networks of the U.S Geological Survey. Some 200 of these events had M ≥3.0.

California↗
USGS1990

Communicating risk information and warnings

Major advances have occurred over the last 20 years about how to effectively communicate risk information and warnings to the public. These lessons have been hard won. Knowledge has mounted on the finding from social scientific studies of risk communication failures, successes and those which fell somewhere in between. Moreover, the last 2 decades have borne witness to the brith, cultivation, and blossoming of information sharing between those physical scientists who discover new information about risk and those communcation scientists who trace its diffusion and then measure pbulic reaction.

Earthquakes & Volcanoes (USGS)↗
USGS1987

Three volcanoes erupt in Alaska

Alaska has over 40 historically active volcanoes and normally averages one eruption a year. Alaskan volcanoes were unusually active in 1986. Augustine, Pavlof, and Akutan volcaneos all erupted vigorously; at one time in April, all three were erupting.

Alaska↗
USGS1988

Otto W. Nuttli; a memorial

With the death of Otto W. Nuttli from cancer on February 9, 1988, the Seismological Society of America lsot one of its most respected and beloved members.

Earthquakes & Volcanoes (USGS)↗
USGS1991

Mid-continent earthquake zones; lessons from New Madrid, Missouri

Many seismically active regions occur throughout the world as concentrated zones surrounded by the relatively stable crust of shields or platforms. Examples occur in central and eastern North America, northeastern Brazil, Australia, Norway, Svalbard, Greenland, and other places. Some of these zones, such as those at New Madrid, Missouri, and in the St. Lawrence Valley on the Canadian border, extend over relatively large areas and are marked by a high level of seismicity. Others, such as that near Anna Ohio, are smaller, and the level of activity is lower. Some zones are occasinoally sites for major earthquakes which, if they are in populated regions, can cause widespread destrucion and loss of life.

Missouri↗
USGS1988

Aerial views of the San Andreas Fault

These aerial photographs of the San Andreas fault were taken in 1965 by Robert E. Wallace of the U.S Geological Survey. The pictures were taken with a Rolliflex camera on 20 format black and white flim; Wallace was aboard a light, fixed-wing aircraft, flying mostly at low altitudes. He photographed the fault from San Francisco near its north end where it enters by the Salton Sea. These images represent only a sampling of the more than 300 images prodcued during this project. All the photographs reside in the U.S Geological Survey Library in Menlo Park, California.

California↗
USGS1992

Small explosions interrupt 3-year quiescence at Mount St. Helens, Washington

On December 11, 1989, geologists working in the crater at Mount St. Helens discovered two thin layers of ash separated by fresh snow-clear evidence that at least two small explosions had occurred recently. The explosions were neither seen nor heard, but on December 7 scientists suspected that a small ash-producing explosion had occurred when seismometers near the volcano recorded a long explosion-like signal, and titlt and displacement meters showed minor deformation of the dome. There were no other large seismic signals to account for the second ash layer, which was most likely associated with one of several smaller signals in early December. The December ash-producing explosions were the first eruptive activity at Mount St. Helens since October 1986. There have been at least five more ash-producing explosions since December 1989, all without recognized seismic or other geophysical precursors. The ash from these explosions appears to be pulverized pieces of dacite dome. The absence of glass shards in the ash suggests that no new magmatic material was ejected. Several of the explosions were accompanied by snow and rock avalanches, pyroclastic flows, ballistic showers, and debris flows. These ash-producing explosions are part of a series of at least 28 explosion-like seismic events that began on August 24, 989. Seismic signals from these events resemble those associated with confirmed ash-producing explosions in April-May 1986. Yet not all of the 1989-1991 events produced ash plumes. Excellent visual observations during four of the events indicated that neither a steam nor ash plume was generated. There is little information about the other events because they occurred when the mountain was not visible, nor was there physical evidence of ashfall or surface changes when scientists visited the crater days to weeks alter. Considerable deformation of the north side of the dome occurred during the series of explosion-like seismic events. Sections of the dome slumped northward and two new vents were formed. However, monitoring the changes associated with individual events was often impossible because several key electronic-distance-meter (EDM) targets and tiltmeters were destroyed by the series of events.

Washington↗
USGS1988

Earthquake warning system for Japan Railways’ bullet train; implications for disaster prevention in California

In Japan, the level of public awareness of the dangers of earthquakes is high. The 1923 Kanto earthquake killed about 120,000 people out of a total Japanese population of about 50 million; an equivalent disaster in the U.S would involve 600,000 deaths. Today, Japanese society is well aware of the prediction of the Tokai earthquake. It is estimated by the Tokyo earthquake. It is estimated by the Tokyo muncipal government that this predicted earthquake could kill 30,000 people. (this estimate is viewed by many as conservative; other Japanese government agencies have made estimates but they have not been published.) Reduction in the number deaths from 120,000 to 30,000 between the Kanto earthquake and the predicted Tokai earthquake is due in large part to the reduction in the proportion of wooden construction (houses).

Earthquakes & Volcanoes (USGS)↗
USGS1988

The fir trees have moved

Trees show a record of the great Kanto earthquake of 1923 in Japan. Two minutes before noon on the morning of September 1, 1923, the Great Kanto earthquake occurred with a magnitude of 7.9 in the northern part of Mizukuma in Sagmi Prefecture, Japan. Fires broke out immediately following the earthquake, causing great damage in Tokyo and in Kanagawa. Deaths totaled 99,331 persons, with 43,476 missing; 128,266 houses partially destroyed, and 447,128 houses were destroyed by fire. Large earth movements occurred and there were innumerable landslides. Along the Kanto coastline, waves came crashing into the harbors; at Misaki the height of the waves was six meters, and 8.1 meters at Sunozaki. At Tokyo the amplitude of the vibrations renged from 14 to 20 centimeters and at Odawara they were estimated to have reached 80 centimeters.

Earthquakes & Volcanoes (USGS)↗
USGS1991

Don’t fence us in

When I was a graduate student around 1950 I used to read the entire Bulletin of the Seismological Society of America. it was a pwoerful and inspiring educational experience, with an effect quite different from that of the more usual process of looking up a few articles in the chain of references in a subject of current interest. Reading the entire journal reveals how ideas, techniques, and seismologists appear and evolve. It is likely the best substitute for a firsthand personal experience with the early development of the field. And in spite of, or perhaps because of, the missteps, the wasted effort, and the lack of sophistication that those first volumes reveal, the reader can sense the opportunity and be inspired by the vibrancy of the young subject.

Earthquakes & Volcanoes (USGS)↗
USGS1987

NCEER seminars on earthquakes

In May of 1986, the National Center for Earthquake Engineering Research (NCEER) in Buffalo, New York, held the first seminar in its new monthly forum called Seminars on Earthquakes. The Center's purpose in initiating the seminars was to educate the audience about earthquakes, to facilitate cooperation between the NCEER and visiting researchers, and to enable visiting speakers to learn more about the NCEER

Earthquakes & Volcanoes (USGS)↗