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Papers by Selena Billington
Bulletin of the Seismological Society of America, Apr 1, 1982
This paper describes a new method which is used in the process of determining composite focal mec... more This paper describes a new method which is used in the process of determining composite focal mechanism solutions to objectively sort earthquakes into sets in which the P -wave first-motion data are compatible. For a network of n stations, each one of which can record either of two first motions (dilatation or compression), there are 2 n mathematically possible patterns of first motions; only a few of these mathematically possible patterns are physically possible for a double-couple source. A comparison is made between the observed first-motion data from a set of earthquakes in a small source region to each of the 2n mathematically possible patterns. The comparison results in two parameters being assigned to each of the patterns: (1) the number of earthquakes which have first motions compatible with the pattern; and (2) the number of actual first-motion data for those earthquakes. Generally, one finds only a few patterns with high parameter values, and which are based on data from independent subsets of earthquakes. In all the cases examined so far, these few patterns are physically possible; i.e., they are compatible with double-couple focal mechanism solutions. The focal mechanism solution determined from a selected pattern of first motion is a composite solution because it is based on the first-motion data from a number of earthquakes.
Pure and Applied Geophysics, 1992
The accuracy and precision of microseismic event locations were measured, analyzed, and compared ... more The accuracy and precision of microseismic event locations were measured, analyzed, and compared for two types of location systems: "analog" and "digital". In the first system, relative times of first arrival were estimated from analog signals using automated hardware circuitry; station positions were estimated from mine map coordinates; and event locations were determined using the BLD (Blake, Leighton, and Duvall) direct solution method. In the second system, arrival times were manually measured during interactive displays of digital waveforms; station coordinates were surveyed; and the SW-GBM (Salamon and Wiebols; Godson, Bridges, and McKavanagh) direct basis function was used to solve for locations. Both systems assume constant isotropic seismic velocity of slightly different magnitude. Two data sets, calibration blast signals with known source site and origin time, and microseismic event signals, were recorded by each location system employing the same array of high-frequency (5 kHz) accelerometers with 150 m maximum dimension. The calibration blast tests indicated a location precision of _+2 m and accuracy of • 10 m for the analog system. Location precision and accuracy for the digital system measured • 1 m and _+ 8 m, respectively. Numerical experiments were used to assess the contributions of errors in velocity, arrival times, and station positions on the location accuracy and precision for each system. Measured and estimated errors appropriate to each system for microseismic events were simulated in computing source locations for comparison with exact synthetic event locations. Discrepancy vectors between exact locations and locations calculated with known data errors averaged 7.7 and 1.4 m for the analog and digital systems, respectively. These averages are probably more representative of the location precision of microseismic events, since the calibration blast tests produce impulsive seismic arrivals resulting in smaller arrival-time pick errors in the analog system. For both systems, location accuracy is limited by inadequate modeling of the velocity structure. Consequently, when isotropic velocity models are used in the travel-time inversions, the increased effort expended with the digital location system does not, for the particular systems studied, result in increased accuracy.
Geophysical Research Letters, Feb 1, 1975
Application of the method of Joint Hypocenter Determination (JHD) to carefully determined arrival... more Application of the method of Joint Hypocenter Determination (JHD) to carefully determined arrival time data from a small network of sensitive and well-distributed local
As the Nation's principal conservation agency, the Department of the Interior has responsibility ... more As the Nation's principal conservation agency, the Department of the Interior has responsibility for most of our nationally-owned public lands and natural resources. This includes fostering sound use of our land and water resources; protecting our fish, wildlife, and biological diversity; preserving the environmental and cultural values of our national parks and historical places; and providing for the enjoyment of life through outdoor recreation. The Department assesses our energy and mineral resources and works to ensure that their development is in the best interests of all our people by encouraging stewardship and citizen participation in their care. The Department also has a major responsibility for American Indian reservation communities and for people who live in island territories under U.S. administration.
Bulletin of the Seismological Society of America, Dec 1, 1985
Geological Society of America eBooks, Apr 5, 2015
Bulletin of the Seismological Society of America, Feb 1, 1986
... BY ER ENGDAHL AND SELENA BILLINGTON ... However, long-period waves reflected from boundaries ... more ... BY ER ENGDAHL AND SELENA BILLINGTON ... However, long-period waves reflected from boundaries with sharp long-period impedance contrasts, such as the sea bottom and the sediment-basement interface, are strongly recorded. ...
Geology, 1977
Seismological evidence based on the spatial distribution and focal mechanism solutions of mantle ... more Seismological evidence based on the spatial distribution and focal mechanism solutions of mantle earthquakes in the Hindu Kush Pamir region supports a model in which suboceanic lithosphere that existed between the converging Eurasian and Indian continents is subducted into the upper mantle. Two lines of evidence support this model. First, a careful selection of well-defined hypocenters in the region from
International Journal of Rock Mechanics and Mining Sciences, 1997
, an underground mine in the Book Cliffs coal mining district of eastern Utah experienced a Mt 3.... more , an underground mine in the Book Cliffs coal mining district of eastern Utah experienced a Mt 3.6 seismic event. The event coincided with the crushing out of 24 18.2 m x 18.2 m x 2.7 m (seam height) pillars encompassing an area of nearly 15,000 m 2. Seismic stations of the University of Utah array, Bureau of Reclamation arrays, and other western seismic stations recorded the event. Digital recordings from the University of Utah provided 41 waveforms for first-motion polarity determinations. All but three reliable polarity readings were dilatations. Source parameter and radiated seismic energy determinations were made using four of the University of Utah three-component stations. Attenuation-corrected P-wave and S-wave radiated energies were determined. The sum of P-and S-wave radiated energies is 1.5-7.1 GJ, depending on the attenuation model. For comparison with the radiated energy, the maximum possible strain energy in the crushed pillars is estimated as 4.1 GJ. Given other energy-absorbing processes involved in the damage, additional sources of energy beyond the pillar strain energy are required. Six scenarios for the event mechanism are examined for consistency with the seismic analysis and on-site damage observations. This study suggests that this catastrophic coal bump was precipitated by a subsidence-related fault slip, with normal slip on a fault in close proximity to the mine workings.
Journal of Geophysical Research, Aug 10, 1982
... the trench axis. The island network located none of these events and detected P phases for on... more ... the trench axis. The island network located none of these events and detected P phases for only three of them. Ray tracing shows that the islands lie in a geometricshadow zone for events on the outer trench slope. The best ...
Mining-induced microseismicity data collected by the U.S. Bureau of Mines in a hard-rock mine wer... more Mining-induced microseismicity data collected by the U.S. Bureau of Mines in a hard-rock mine were analyzed for spatial and temporal patterns that might prove useful for prediction of rock bursts or assessment of rock mass damage changes. Pattern attributes described and illustrated in the previous report (part 1) were applied to the study of aftershock sequences associated with two different stopes. The aftershock sequences were spatially and temporally fractal, and the fractality was maintained for up to 16 h following a sequence progenitor. This suggests mechanical interdependency among the aftershocks. No statistical difference was found in the distributions of fractal dimensions when comparing two different stopes or when comparing aftershock sequences initiated by blasts or bumps. This suggests a lack of sensitivity to both stress perturbation mechanism and local damage states. However, differences between the two stopes were found in other sequence attributes that support inferred differences in the magnitude of stress concentrations and damage near each stope, and over time as a stope is developed. lOeophysicist. 2Electronics engin~r.
Mining-induced microseismicity data collected by the U.S. Bureau of Mines in a hard-rock mine wer... more Mining-induced microseismicity data collected by the U.S. Bureau of Mines in a hard-rock mine were analyzed for spatial and temporal patterns that might prove useful for prediction of rock bursts or assessment of rock mass damage changes. Pattern attributes described and illustrated in the previous report (part 1) were applied to the study of aftershock sequences associated with two different stopes. The aftershock sequences were spatially and temporally fractal, and the fractality was maintained for up to 16 h following a sequence progenitor. This suggests mechanical interdependency among the aftershocks. No statistical difference was found in the distributions of fractal dimensions when comparing two different stopes or when comparing aftershock sequences initiated by blasts or bumps. This suggests a lack of sensitivity to both stress perturbation mechanism and local damage states. However, differences between the two stopes were found in other sequence attributes that support inferred differences in the magnitude of stress concentrations and damage near each stope, and over time as a stope is developed. lOeophysicist. 2Electronics engin~r.
CRC Press eBooks, Dec 17, 2020
SEG Technical Program Expanded Abstracts 1992, 1992
Maurice Ewing series, Mar 20, 2013
Dress Hermeneutics and the Hebrew Bible
Bulletin of the Seismological Society of America, 1985
Bulletin of the Seismological Society of America, Apr 1, 1982
This paper describes a new method which is used in the process of determining composite focal mec... more This paper describes a new method which is used in the process of determining composite focal mechanism solutions to objectively sort earthquakes into sets in which the P -wave first-motion data are compatible. For a network of n stations, each one of which can record either of two first motions (dilatation or compression), there are 2 n mathematically possible patterns of first motions; only a few of these mathematically possible patterns are physically possible for a double-couple source. A comparison is made between the observed first-motion data from a set of earthquakes in a small source region to each of the 2n mathematically possible patterns. The comparison results in two parameters being assigned to each of the patterns: (1) the number of earthquakes which have first motions compatible with the pattern; and (2) the number of actual first-motion data for those earthquakes. Generally, one finds only a few patterns with high parameter values, and which are based on data from independent subsets of earthquakes. In all the cases examined so far, these few patterns are physically possible; i.e., they are compatible with double-couple focal mechanism solutions. The focal mechanism solution determined from a selected pattern of first motion is a composite solution because it is based on the first-motion data from a number of earthquakes.
Pure and Applied Geophysics, 1992
The accuracy and precision of microseismic event locations were measured, analyzed, and compared ... more The accuracy and precision of microseismic event locations were measured, analyzed, and compared for two types of location systems: "analog" and "digital". In the first system, relative times of first arrival were estimated from analog signals using automated hardware circuitry; station positions were estimated from mine map coordinates; and event locations were determined using the BLD (Blake, Leighton, and Duvall) direct solution method. In the second system, arrival times were manually measured during interactive displays of digital waveforms; station coordinates were surveyed; and the SW-GBM (Salamon and Wiebols; Godson, Bridges, and McKavanagh) direct basis function was used to solve for locations. Both systems assume constant isotropic seismic velocity of slightly different magnitude. Two data sets, calibration blast signals with known source site and origin time, and microseismic event signals, were recorded by each location system employing the same array of high-frequency (5 kHz) accelerometers with 150 m maximum dimension. The calibration blast tests indicated a location precision of _+2 m and accuracy of • 10 m for the analog system. Location precision and accuracy for the digital system measured • 1 m and _+ 8 m, respectively. Numerical experiments were used to assess the contributions of errors in velocity, arrival times, and station positions on the location accuracy and precision for each system. Measured and estimated errors appropriate to each system for microseismic events were simulated in computing source locations for comparison with exact synthetic event locations. Discrepancy vectors between exact locations and locations calculated with known data errors averaged 7.7 and 1.4 m for the analog and digital systems, respectively. These averages are probably more representative of the location precision of microseismic events, since the calibration blast tests produce impulsive seismic arrivals resulting in smaller arrival-time pick errors in the analog system. For both systems, location accuracy is limited by inadequate modeling of the velocity structure. Consequently, when isotropic velocity models are used in the travel-time inversions, the increased effort expended with the digital location system does not, for the particular systems studied, result in increased accuracy.
Geophysical Research Letters, Feb 1, 1975
Application of the method of Joint Hypocenter Determination (JHD) to carefully determined arrival... more Application of the method of Joint Hypocenter Determination (JHD) to carefully determined arrival time data from a small network of sensitive and well-distributed local
As the Nation's principal conservation agency, the Department of the Interior has responsibility ... more As the Nation's principal conservation agency, the Department of the Interior has responsibility for most of our nationally-owned public lands and natural resources. This includes fostering sound use of our land and water resources; protecting our fish, wildlife, and biological diversity; preserving the environmental and cultural values of our national parks and historical places; and providing for the enjoyment of life through outdoor recreation. The Department assesses our energy and mineral resources and works to ensure that their development is in the best interests of all our people by encouraging stewardship and citizen participation in their care. The Department also has a major responsibility for American Indian reservation communities and for people who live in island territories under U.S. administration.
Bulletin of the Seismological Society of America, Dec 1, 1985
Geological Society of America eBooks, Apr 5, 2015
Bulletin of the Seismological Society of America, Feb 1, 1986
... BY ER ENGDAHL AND SELENA BILLINGTON ... However, long-period waves reflected from boundaries ... more ... BY ER ENGDAHL AND SELENA BILLINGTON ... However, long-period waves reflected from boundaries with sharp long-period impedance contrasts, such as the sea bottom and the sediment-basement interface, are strongly recorded. ...
Geology, 1977
Seismological evidence based on the spatial distribution and focal mechanism solutions of mantle ... more Seismological evidence based on the spatial distribution and focal mechanism solutions of mantle earthquakes in the Hindu Kush Pamir region supports a model in which suboceanic lithosphere that existed between the converging Eurasian and Indian continents is subducted into the upper mantle. Two lines of evidence support this model. First, a careful selection of well-defined hypocenters in the region from
International Journal of Rock Mechanics and Mining Sciences, 1997
, an underground mine in the Book Cliffs coal mining district of eastern Utah experienced a Mt 3.... more , an underground mine in the Book Cliffs coal mining district of eastern Utah experienced a Mt 3.6 seismic event. The event coincided with the crushing out of 24 18.2 m x 18.2 m x 2.7 m (seam height) pillars encompassing an area of nearly 15,000 m 2. Seismic stations of the University of Utah array, Bureau of Reclamation arrays, and other western seismic stations recorded the event. Digital recordings from the University of Utah provided 41 waveforms for first-motion polarity determinations. All but three reliable polarity readings were dilatations. Source parameter and radiated seismic energy determinations were made using four of the University of Utah three-component stations. Attenuation-corrected P-wave and S-wave radiated energies were determined. The sum of P-and S-wave radiated energies is 1.5-7.1 GJ, depending on the attenuation model. For comparison with the radiated energy, the maximum possible strain energy in the crushed pillars is estimated as 4.1 GJ. Given other energy-absorbing processes involved in the damage, additional sources of energy beyond the pillar strain energy are required. Six scenarios for the event mechanism are examined for consistency with the seismic analysis and on-site damage observations. This study suggests that this catastrophic coal bump was precipitated by a subsidence-related fault slip, with normal slip on a fault in close proximity to the mine workings.
Journal of Geophysical Research, Aug 10, 1982
... the trench axis. The island network located none of these events and detected P phases for on... more ... the trench axis. The island network located none of these events and detected P phases for only three of them. Ray tracing shows that the islands lie in a geometricshadow zone for events on the outer trench slope. The best ...
Mining-induced microseismicity data collected by the U.S. Bureau of Mines in a hard-rock mine wer... more Mining-induced microseismicity data collected by the U.S. Bureau of Mines in a hard-rock mine were analyzed for spatial and temporal patterns that might prove useful for prediction of rock bursts or assessment of rock mass damage changes. Pattern attributes described and illustrated in the previous report (part 1) were applied to the study of aftershock sequences associated with two different stopes. The aftershock sequences were spatially and temporally fractal, and the fractality was maintained for up to 16 h following a sequence progenitor. This suggests mechanical interdependency among the aftershocks. No statistical difference was found in the distributions of fractal dimensions when comparing two different stopes or when comparing aftershock sequences initiated by blasts or bumps. This suggests a lack of sensitivity to both stress perturbation mechanism and local damage states. However, differences between the two stopes were found in other sequence attributes that support inferred differences in the magnitude of stress concentrations and damage near each stope, and over time as a stope is developed. lOeophysicist. 2Electronics engin~r.
Mining-induced microseismicity data collected by the U.S. Bureau of Mines in a hard-rock mine wer... more Mining-induced microseismicity data collected by the U.S. Bureau of Mines in a hard-rock mine were analyzed for spatial and temporal patterns that might prove useful for prediction of rock bursts or assessment of rock mass damage changes. Pattern attributes described and illustrated in the previous report (part 1) were applied to the study of aftershock sequences associated with two different stopes. The aftershock sequences were spatially and temporally fractal, and the fractality was maintained for up to 16 h following a sequence progenitor. This suggests mechanical interdependency among the aftershocks. No statistical difference was found in the distributions of fractal dimensions when comparing two different stopes or when comparing aftershock sequences initiated by blasts or bumps. This suggests a lack of sensitivity to both stress perturbation mechanism and local damage states. However, differences between the two stopes were found in other sequence attributes that support inferred differences in the magnitude of stress concentrations and damage near each stope, and over time as a stope is developed. lOeophysicist. 2Electronics engin~r.
CRC Press eBooks, Dec 17, 2020
SEG Technical Program Expanded Abstracts 1992, 1992
Maurice Ewing series, Mar 20, 2013
Dress Hermeneutics and the Hebrew Bible
Bulletin of the Seismological Society of America, 1985