Artificial Earthquakes
captain wardrobe | 17.01.2005 01:44
this page was found while stumbling around the US defense google search engine
very very strange is it not?
very very strange is it not?
ChangÂ's mountaintop experience
By Debbie Quimby, ERDC PAO
(Left: Frank Chang in 1959)
Mr. Feng-Keng (Frank) Chang retired from the Geotechnical and Structures Laboratory in 1992, after 25 years of service to the federal government. But many years before he came to work for GSL, Chang had an opportunity to go where few men had gone before Â- the Antarctic.
In 1957, Chang was a graduate student at St. Louis University, enrolled in the Department of Geophysics and Geophysical Engineering. At that time, scientists from around the world were planning to conduct geophysical studies at the North and South Poles in an effort to improve their understanding of the earth and its environments. This endeavor, named the International Geophysical Year (IGY), ran from July 1957 to December 1958.
Many in ChangÂ's class were interested in the IGY project, but never thought they would have a chance to participate. In August 1958, ChangÂ's professor recommended him to the National Science Foundation for a part in the U.S. Antarctic Research Program, a continuation of the IGY (the IGY had produced such interesting results that the U.S. and other IGY nations decided to continue their Antarctic work).
Chang was accepted into the program, and after two months training, he and his colleagues joined the last expedition of the IGY-Horlick Mountain Traverse in December 1958. This effort, and others to follow, was commonly known as Deep Freeze IV. ChangÂ's job as Chief Seismologist was to conduct seismic, gravity and magnetic explorations on the Marie Byrd Land Traverse from 1959 to 1960. ChangÂ's group made two traverses into the Antarctic. Between traverses, scientists stayed at Byrd Station, analyzing data, calibrating and repairing equipment.
His group consisted of 23 scientists, all operating out of Byrd Station. From December to midsummer, Chang worked closely with glaciologists to estimate the thickness of the Antarctic ice through the observation of artificial earthquakes.
The method commonly used for determining ice thickness was known as seismic Â"shooting.Â" Developed primarily for finding oil deposits, the technique was borrowed by scientists to measure glacier depths. Chang would generate a small-scale earthquake, then measure the time it took the resulting vibrations to travel through the ice to the underlying rock and back to the surface. This Â"earthquakeÂ" was generated by electrically fired explosives, ranging in size from a few grams to many pounds. TNT was the explosive of choice, since it had less risk of accidents than other explosives in the extremely cold conditions.
In 1959, the average thickness of the ice in western Antarctica was app. 6,000 feet, but many areas ran more than 14,000 feet thick. A seismologistÂ's work in the Antarctic was not much different from that in more temperate zones, but working conditions were restrictive due to the cold, ice and winds.
Living and travel conditions in the Antarctic proved to be a challenge as well. The scientists traveled in Â"sno-cats,Â" vehicles that accommodated two men and their bunks. Supplies were carried on large sleds. Average temperatures during the winter months (April to September) were about 45 degrees below zero, with the lowest temperature during ChangÂ's time in the Antarctic reaching 70 degrees below zero. While on one traverse, the group experienced a blizzard that kept them immobilized for nine days, away from Byrd Station. As if the cold was not enough, Antarctica was and is home to a large, active volcano, app. 13,000 ft. high. Chang spent his free time reading books from the groupÂ's portable library, watching movies, competing in ping-pong tournaments, and learning photo-developing techniques.
Upon his return to the United States, Chang continued his studies and worked at the Geophysical and Polar Research Center at the University of Wisconsin, before coming to work for the Waterways Experiment Station in 1967.
(Left: Frank Chang sits on what will become Chang Peak).
In 1963, the National Science Foundation named a snow-covered subsidiary peak at elevation 2,920 feet in his honor Â- Chang Peak. Chang Peak is located on the northeastern slope of Mount Waesche, in the Executive Committee Range of the Marie Byrd Land. The peak is at -126.63 longitude and Â-77.06 latitude.
In 1974, Chang was awarded the U.S. Antarctic Service Medal for his contributions to the US Antarctic Research Program.
AuthorÂ's note: Frank Chang is now in his 80s and still lives in Vicksburg. He stopped by a couple of weeks ago because his son had found his Â"peakÂ" on the Internet and gave him a printout as a gift. He is still very proud ( understandably so) of his contributions to Antarctic exploration. He told me that he still remembered his time as Â"an extraordinary experienceÂ" and he was Â"thankful for the personal good fortuneÂ" that allowed him to participate. I say Frank Chang is extraordinary and it was our good fortune that he shared his story with us.
http://64.233.183.104/unclesam?q=cache:fxNt57gGYEQJ:www.erdc.usace.army.mil/pls/erdcpub/docs/erdc/docs/frankchang+artificial+earthquake&hl=en&ie=UTF-8
By Debbie Quimby, ERDC PAO
(Left: Frank Chang in 1959)
Mr. Feng-Keng (Frank) Chang retired from the Geotechnical and Structures Laboratory in 1992, after 25 years of service to the federal government. But many years before he came to work for GSL, Chang had an opportunity to go where few men had gone before Â- the Antarctic.
In 1957, Chang was a graduate student at St. Louis University, enrolled in the Department of Geophysics and Geophysical Engineering. At that time, scientists from around the world were planning to conduct geophysical studies at the North and South Poles in an effort to improve their understanding of the earth and its environments. This endeavor, named the International Geophysical Year (IGY), ran from July 1957 to December 1958.
Many in ChangÂ's class were interested in the IGY project, but never thought they would have a chance to participate. In August 1958, ChangÂ's professor recommended him to the National Science Foundation for a part in the U.S. Antarctic Research Program, a continuation of the IGY (the IGY had produced such interesting results that the U.S. and other IGY nations decided to continue their Antarctic work).
Chang was accepted into the program, and after two months training, he and his colleagues joined the last expedition of the IGY-Horlick Mountain Traverse in December 1958. This effort, and others to follow, was commonly known as Deep Freeze IV. ChangÂ's job as Chief Seismologist was to conduct seismic, gravity and magnetic explorations on the Marie Byrd Land Traverse from 1959 to 1960. ChangÂ's group made two traverses into the Antarctic. Between traverses, scientists stayed at Byrd Station, analyzing data, calibrating and repairing equipment.
His group consisted of 23 scientists, all operating out of Byrd Station. From December to midsummer, Chang worked closely with glaciologists to estimate the thickness of the Antarctic ice through the observation of artificial earthquakes.
The method commonly used for determining ice thickness was known as seismic Â"shooting.Â" Developed primarily for finding oil deposits, the technique was borrowed by scientists to measure glacier depths. Chang would generate a small-scale earthquake, then measure the time it took the resulting vibrations to travel through the ice to the underlying rock and back to the surface. This Â"earthquakeÂ" was generated by electrically fired explosives, ranging in size from a few grams to many pounds. TNT was the explosive of choice, since it had less risk of accidents than other explosives in the extremely cold conditions.
In 1959, the average thickness of the ice in western Antarctica was app. 6,000 feet, but many areas ran more than 14,000 feet thick. A seismologistÂ's work in the Antarctic was not much different from that in more temperate zones, but working conditions were restrictive due to the cold, ice and winds.
Living and travel conditions in the Antarctic proved to be a challenge as well. The scientists traveled in Â"sno-cats,Â" vehicles that accommodated two men and their bunks. Supplies were carried on large sleds. Average temperatures during the winter months (April to September) were about 45 degrees below zero, with the lowest temperature during ChangÂ's time in the Antarctic reaching 70 degrees below zero. While on one traverse, the group experienced a blizzard that kept them immobilized for nine days, away from Byrd Station. As if the cold was not enough, Antarctica was and is home to a large, active volcano, app. 13,000 ft. high. Chang spent his free time reading books from the groupÂ's portable library, watching movies, competing in ping-pong tournaments, and learning photo-developing techniques.
Upon his return to the United States, Chang continued his studies and worked at the Geophysical and Polar Research Center at the University of Wisconsin, before coming to work for the Waterways Experiment Station in 1967.
(Left: Frank Chang sits on what will become Chang Peak).
In 1963, the National Science Foundation named a snow-covered subsidiary peak at elevation 2,920 feet in his honor Â- Chang Peak. Chang Peak is located on the northeastern slope of Mount Waesche, in the Executive Committee Range of the Marie Byrd Land. The peak is at -126.63 longitude and Â-77.06 latitude.
In 1974, Chang was awarded the U.S. Antarctic Service Medal for his contributions to the US Antarctic Research Program.
AuthorÂ's note: Frank Chang is now in his 80s and still lives in Vicksburg. He stopped by a couple of weeks ago because his son had found his Â"peakÂ" on the Internet and gave him a printout as a gift. He is still very proud ( understandably so) of his contributions to Antarctic exploration. He told me that he still remembered his time as Â"an extraordinary experienceÂ" and he was Â"thankful for the personal good fortuneÂ" that allowed him to participate. I say Frank Chang is extraordinary and it was our good fortune that he shared his story with us.
http://64.233.183.104/unclesam?q=cache:fxNt57gGYEQJ:www.erdc.usace.army.mil/pls/erdcpub/docs/erdc/docs/frankchang+artificial+earthquake&hl=en&ie=UTF-8
captain wardrobe
Homepage:
http://www.warcrimes.org.uk/captain/murder_inc/tsunami.html
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17.01.2005 04:45
a more technical paper
Convulution and deconvulotion in diges
Convolution and deconvolution operations is by all means a very important aspect of SSI analysis since it influences the input to the seismic analysis. This paper documents some of the convolution/deconvolution procedures which have been implemented into the DIGES code. The 1-D propagation of shear and dilatational waves in typical layered configurations involving a stack of layers overlying a rock is treated by DIGES in a similar fashion to that of available codes, e.g. CARES, SHAKE. For certain configurations, however, there is no need to perform such analyses since the corresponding solutions can be obtained in analytic form. Typical cases involve deposits which can be modeled by a uniform halfspace or simple layered halfspaces. For such cases DIGES uses closed-form solutions. These solutions are given for one as well as two dimensional deconvolution. The type of waves considered include P, SV and SH waves. The non-vertical incidence is given special attention since deconvolution can be defined differently depending on the problem of interest. For all wave cases considered, corresponding transfer functions are presented in closed-form. Transient solutions are obtained in the frequency domain. Finally, a variety of forms are considered for representing the free field motion both in terms of deterministic as well as probabilistic representations. These include (a) acceleration time histories, (b) response spectra (c) Fourier spectra and (d) cross-spectral densities.
cw
artificial intelligence to warn of earthquakes?
17.01.2005 04:52
An earthquake warning system has been developed to provide a time series profile from which vital parameters such as the time until strong shaking begins, the intensity of the shaking, and the duration of the shaking, can be derived.
Interaction of different types of ground motion and changes in the elastic properties of geological media throughout the propagation path result in a highly nonlinear function. We use neural networks to model these nonlinearities and develop learning techniques for the analysis of temporal precursors occurring in the emerging earthquake seismic signal.
The warning system is designed to analyze the first-arrival from the three components of an earthquake signal and instantaneously provide a profile of impending ground motion, in as little as 0.3 sec after first ground motion is felt at the sensors. For each new data sample, at a rate of 25 samples per second, the complete profile of the earthquake is updated. The profile consists of a magnitude-related estimate as well as an estimate of the envelope of the complete earthquake signal.
The envelope provides estimates of damage parameters, such as time until peak ground acceleration (PGA) and duration.
The neural network based system is trained using seismogram data from more than 400 earthquakes recorded in southern California. The system has been implemented in hardware using silicon accelerometers and a standard microprocessor.
The proposed warning units can be used for site-specific applications, distributed networks, or to enhance existing distributed networks. By producing accurate, and informative warnings, the system has the potential to significantly minimize the hazards of catastrophic ground motion.
put P-Wave in your search engine
cw
why hidden?
17.01.2005 04:54
what policys are broken?
strange to hide a found articles on the P-Wave from military sites?
cw