 |
|
Deadly mine 'bump' was recorded as seismic event
August 20, 2007Magnitude 1.6 seismic waves indicate downward motion
The University of Utah Seismograph Stations recorded a magnitude-1.6 seismic event at the time of a Thursday, Aug. 16 "bump" that killed and injured rescuers at a Utah coal mine where six miners were trapped by an Aug. 6 collapse.
Seismic waves from the event at about 6:39 p.m. MDT Thursday indicate downward motion, consistent with further settling and collapse within the mountain where the Crandall Canyon mine is located.
The University of Utah Seismograph Stations recorded the original mine collapse as a magnitude-3.9 earthquake at 2:48 a.m. MDT Aug. 6. The downward motion of waves from that event - like subsequent "after events," including the one Thursday evening - are indicative of collapse, not of motion generated by natural or "tectonic" earthquakes.
Seismologists at the University of Utah, the U.S. Geological Survey and the University of California, Berkeley, have pointed to increasingly strong evidence that the magnitude-3.9 seismic event on Aug. 6 was the mine collapse itself, not a natural earthquake.
Thursday night's bump was very shallow. Initial seismograph recordings indicated it was less than one-tenth of a mile deep, but considering uncertainties in determining depths of such seismic events, indications are the seismic event happened at a depth of less than one mile. This is quite unlike natural earthquakes, which are deeper.
As of Friday morning, Aug. 17, 22 seismic "after-events" have been recorded within about 2 miles of the mine. Twelve of those were within two days of the original collapse. However, the University of Utah Seismograph Stations installed five new seismometers near the mine, so more of the small seismic waves now are being detected. Thursday night's deadly "bump" was detected both by the new seismometers and by part of the university's pre-existing seismic network.
"These events seem to be related to the ongoing settling of the rock mass following the main collapse on Aug. 6," said Relu Burlacu, network manager for the University of Utah Seismograph Stations.
Coal mining takes place in an arc-shaped area in eastern Utah. An analysis of years of seismicity in that area by Walter Arabasz, director of the University of Utah Seismograph Stations, and his colleagues indicates that less than 2 percent of all seismicity in the coal-mining region is due to natural or tectonic earthquakes, and that 98 percent of the seismicity is caused by mining activity.
University of Utah
The University of Utah Seismograph Stations recorded the original mine collapse as a magnitude-3.9 earthquake at 2:48 a.m. MDT Aug. 6. The downward motion of waves from that event - like subsequent "after events," including the one Thursday evening - are indicative of collapse, not of motion generated by natural or "tectonic" earthquakes.
Seismologists at the University of Utah, the U.S. Geological Survey and the University of California, Berkeley, have pointed to increasingly strong evidence that the magnitude-3.9 seismic event on Aug. 6 was the mine collapse itself, not a natural earthquake.
Thursday night's bump was very shallow. Initial seismograph recordings indicated it was less than one-tenth of a mile deep, but considering uncertainties in determining depths of such seismic events, indications are the seismic event happened at a depth of less than one mile. This is quite unlike natural earthquakes, which are deeper.
As of Friday morning, Aug. 17, 22 seismic "after-events" have been recorded within about 2 miles of the mine. Twelve of those were within two days of the original collapse. However, the University of Utah Seismograph Stations installed five new seismometers near the mine, so more of the small seismic waves now are being detected. Thursday night's deadly "bump" was detected both by the new seismometers and by part of the university's pre-existing seismic network.
"These events seem to be related to the ongoing settling of the rock mass following the main collapse on Aug. 6," said Relu Burlacu, network manager for the University of Utah Seismograph Stations.
Coal mining takes place in an arc-shaped area in eastern Utah. An analysis of years of seismicity in that area by Walter Arabasz, director of the University of Utah Seismograph Stations, and his colleagues indicates that less than 2 percent of all seismicity in the coal-mining region is due to natural or tectonic earthquakes, and that 98 percent of the seismicity is caused by mining activity.
University of Utah
Study uses satellite imagery to identify active magma systems in East Africa's Rift Valley
A team from the University of Miami, University of El Paso and University of Rochester have employed Interferometric Synthetic Aperture Radar (InSAR) images compiled over a decade to study volcanic activity in the African Rift. The study, published in the November issue of Geology, studies the section of the rift in Kenya.
Fatal mine collapse covered 50 acres
New calculations show that the deadly Crandall Canyon mine collapse - which registered as a magnitude-3.9 earthquake - began near where miners were excavating coal and quickly grew to a 50-acre cave-in, University of Utah seismologists say in a report on the tragedy.
University of Nevada scientists gauge earthquake hazards through study of precariously balance rocks
A seismological research team from the University of Nevada, Reno is finding ways to make precariously balanced rocks talk. In so doing, they are unlocking valuable scientific information in assessing seismic hazards in areas throughout the West.
Media invitation: Nuclear test ban spurs research into UK`s rocky foundations
The vital role UK earth scientist play in monitoring the Comprehensive Nuclear Test Ban Treaty (CTBT), and how their research is leading to a greater understanding of what the Earth is like under the British Isles, is the subject of a two-day meeting in London on the 7th and 8th of February. Sponsored by the Royal Astronomical Society and the British Geophysical Association, the international gathering of seismologists and other earth scientists takes place in the Geological Society`s lecture theatre in Burlington House, Piccadilly, London W1. The meeting is open and media representatives are welcome. Full details are available at http://www.gsrg.nmh.ac.uk/ras_mtg.htm. Seismology - the detec
More Seismic Event Current Events and Seismic Event News Articles
 |
Monitoring the Comprehensive Nuclear-Test-Ban Treaty: Seismic Event Discrimination and Identification (Pageoph Topical Volumes) by William R. Walter (Editor), Hans E. Hartse (Editor) The problem of identifying small-magnitude banned nuclear tests and discriminating between such tests and the background of earthquakes and mining-related seismic events, is a challenging research problem. Because they emphasize CTBT verification research, the 12 papers in this special volume primarily address regional data recorded by a variety of arrays, broadband stations, and temporarily deployed stations. Nuclear explosions, earthquakes, mining-related explosions, mine collapses, single-charge and ripple-fired chemical explosions from Europe, Asia, North Africa and North America are all studied. In September 1996, the United Nations General Assembly adopted the Comprehensive Nuclear-Test-Ban Treaty (CTBT), prohibiting nuclear explosions worldwide, in all environments. The... |
 |
Small Seismic Event Brummbaer (Primary Contributor) |
|
WHO guidelines often lack evidence, study finds; 'Pretty seismic event,' Lancet editor says.(World Wire): An article from: Winnipeg Free Press by Gale Reference Team (Author) This digital document is an article from Winnipeg Free Press, published by Thomson Gale on May 8, 2007. The length of the article is 437 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser. Citation Details Title: WHO guidelines often lack evidence, study finds; 'Pretty seismic event,' Lancet editor says.(World Wire) Author: Gale Reference Team Publication: Winnipeg Free Press (Magazine/Journal) Date: May 8, 2007 Publisher: Thomson Gale Page: a12 Distributed by Thomson... | |
|
Ninety-second Congress, First Session on Extent of Present Capabilities for Detecting and Determining Nature of Underground Events (Status of Current Technology to Identify Seismic Events as Natural or Man-Made) by Joint Committee on Atomic Energy (Author) Hearings before the Subcommittee on Research, Development, and Radiation of the Joint Committee on Atomic Energy Congress of the United States | |
 |
Advances in Seismic Event Location (Modern Approaches in Geophysics) by C.H. Thurber (Editor), Nitzan Rabinowitz (Editor) Advances in Seismic Event Location provides a broad overview of the fundamental issues involved in seismic event location, and presents a variety of state-of-the-art location methods and applications at a wide range of spatial scales. Three important themes in the book are: seismic monitoring for a Comprehensive Nuclear-Test-Ban Treaty (CTBT), seismic event location in three-dimensional Earth models, and methods for multiple-event location. Each chapter contains background material to help readers less familiar with the topics covered, as well as to provide abundant references for readers interested in probing deeper into a topic. However, most of the emphasis is on recent advances in methodology and their application. Audience: The book is intended primarily for academic and ... |
|
Seismic Events Probabilistic Risk Assessment (Pvp, Vol 79) by Pei-Ying Chen (Author) | |
 |
Induced Seismic Events (Pageoph Topical Volumes) by Peter Knoll (Author), Georg Kowalle (Author) Induced seismic events are of high scientific and economic significance. They are the result of human activities interacting with regional and local tectonics, changing the local crustal stress state by mining, extraction of rock masses, injection of fluids into the rock massif, and by changing the surface loading and pore pressure state near large reservoirs. Within Europe the study of induced seismic events has a long tradition and international scientific organizations have actively stimulated the co-operation in this field. During its General Assembly in September 1994, the European Seismological Society organized the symposium "Induced Seismic Events". The focus of this symposium was concentrated on induced events in central and eastern Europe, as well as in the former Soviet Union.... |
|
Architectural Glass to Resist Seismic and Extreme Climatic Events by R. A. Behr (Editor) Glass is increasingly being used as a structural material in new buildings and the building envelope may consist entirely of glass or a building may be clad with glass. This trend for steel-framed, glass clad buildings instead of traditional materials such as brick and concrete has inherent problems. One of the major problems is the performance of the glazing during earthquakes and extreme climatic events such as windstorms and heavy snow loads. This authoritative book reviews the current state-of-the art in glass and glazing technology to resist failure due to these natural events. | |
 |
Monitoring the Comprehensive Nuclear-Test-Ban Treaty by Frode Ringdal (Editor), Brian L.N. Kennett (Editor) Presents recent advances both in the methodology of locating seismic events and in the large-scale international regional calibration effort that is now underway. Softcover. |
|
Procedure for routine analyses and classification of seismic events at the Hawaiian Volcano Observatory: Part 1 (Open-file report / Department of the Interior, U.S. Geological Survey) by Robert Y Koyanagi (Author) |
| © 2009 BrightSurf.com |