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INL Seismic Monitoring Annual Report: January 1, 2007 - December 31, 2007

Description: During 2007, the INL Seismic Monitoring Program evaluated 2,515 earthquakes from around the world, the western United States, and local region of the eastern Snake River Plain. 671 earthquakes and man-made blasts occurred within the local region outside and within a 161-km (or 100-mile) radius of INL. Of these events, eleven were small to moderate size earthquakes ranging in magnitude from 3.0 to 4.8. 341 earthquakes occurred within the 161-km radius of INL and the majority of these earthquakes were located in active regions of the Basin and Range Province that surrounds the ESRP. Three earthquakes were located within the ESRP at Craters of the Moon National Monument. The earthquakes were of Mc 0.9, 1.4, and 1.8. Since 1972, INL has recorded 36 small-magnitude microearthquakes (M < 2.0) within the ESRP.
Date: September 1, 2008
Creator: Payne, S. J.; Carpenter, N. S.; Hodges, J. M. & Berg, R. G.
Partner: UNT Libraries Government Documents Department

INL Seismic Monitoring Annual Report: January 1, 2011 - December 31, 2011

Description: During 2011, the Idaho National Laboratory Seismic Monitoring Program evaluated 21,928 independent triggers that included earthquakes from around the world, the western United States, and local region of the Snake River Plain. Seismologists located 2,063 earthquakes and man-made blasts within and near the 161-km (or 100-mile) radius of the Idaho National Laboratory. Of these events, 16 were small-to-moderate size earthquakes ranging in magnitude (M) from 3.0 to 4.4. Within the 161-km radius, the majority of 941 earthquakes (M < 4.4) occurred in the active regions of the Basin and Range Province with only six microearthquakes occurring in the Snake River Plain. In the northern and southeastern Basin and Range, eight earthquake swarms occurred and included over 325 events. Five of the Snake River Plain earthquakes were located within and near the northern and southern ends of the Great Rift volcanic rift zone. All have anomalously deep focal depths (16 to 38 km) and waveforms indicative of fluid movement at mid- and lower-crustal levels and are a continuation of activity observed at Craters of the Moon National Monument since 2007. Since 1972, the Idaho National Laboratory has recorded 55 small-magnitude microearthquakes (M = 2.2) within the eastern Snake River Plain and 25 deep microearthquakes (M = 2.3) in the vicinity of Craters of the Moon National Monument.
Date: December 1, 2012
Creator: Payne, S. J.; Hodges, J. M.; Berg, R. G. & Bruhn, D. F.
Partner: UNT Libraries Government Documents Department

Enhanced Geothermal System Potential for Sites on the Eastern Snake River Plain, Idaho

Description: The Snake River volcanic province overlies a thermal anomaly that extends deep into the mantle and represents one of the highest heat flow provinces in North America (Blackwell and Richards, 2004). This makes the Snake River Plain (SRP) one of the most under-developed and potentially highest producing geothermal districts in the United States. Elevated heat flow is typically highest along the margins of the topographic SRP and lowest along the axis of the plain, where thermal gradients are suppressed by the Snake River aquifer. Beneath this aquifer, however, thermal gradients rise again and may tap even higher heat flows associated with the intrusion of mafic magmas into the mid-crustal sill complex (e.g., Blackwell, 1989).
Date: September 1, 2013
Creator: Podgorney, Robert K; Wood, Thomas R.; McLing, Travis L; Mines, Gregory; Plummer, Mitchell A; McCurry, Michael et al.
Partner: UNT Libraries Government Documents Department

INL Seismic Monitoring Annual Report: January 1, 2005 - December 31, 2005

Description: During 2005, the Idaho National Laboratory (INL) recorded 2390 independent triggers from earthquakes both within the region and from around the world. 38 small to moderate size earthquakes ranging in magnitude from 3.0 to 5.7 occurred within and outside the 161-km (100-mile) radius of INL. Earthquakes activity occurred in areas that have experienced seismic activity in the past, the Basin and Range northwest of the INL, southwestern Montana, Yellowstone Park, Wyoming, Jackson, Wyoming, and southeastern Idaho. INL recorded the July 26, 2005 body-wave magnitude (mb) 5.7 Dillon, Montana earthquake and 100’s of associated aftershocks. Local residents felt the earthquake and experienced minor damage. The mb 5.7 main shock was located more than 170 km (105 miles) from INL facilities and was not felt. The main shock did not trigger any strong-motion accelerographs (SMAs) located within INL buildings. Free-field SMAs and accelerometers co-located with seismic stations recorded acceleration data. Peak horizontal and vertical accelerations range from 0.0077 to 0.0006 g. There were 449 earthquakes with magnitudes up to 4.6 that occurred within the 161-km radius of the INL in the Basin and Range surrounding the eastern Snake River Plain (ESRP). No earthquakes occurred within the INL boundaries or the ESRP. The largest earthquake occurred on October 31, 2005 and had a moment magnitude (Mw) 4.6. It was located north of Leadore, Idaho at a distance of 100 km (62 miles) from INL. The earthquake did not trigger SMAs located within INL buildings. Free-field SMAs and accelerometers co-located at seismic stations recorded peak horizontal and vertical accelerations that ranged from 0.0003 to 0.0030 g.
Date: September 1, 2006
Creator: Payne, S. J.; Holland, A. A.; Hodges, J. M. & Berg, R. G.
Partner: UNT Libraries Government Documents Department

INL Seismic Monitoring Annual Report: January 1, 2006 - December 31, 2006

Description: During 2006, the Idaho National Laboratory (INL) recorded 1998 independent triggers from earthquakes both within the region and from around the world. Fifteen small to moderate size earthquakes ranging in magnitude from 3.0 to 4.5 occurred within and outside the 161-km (100-mile) radius of INL. There were 357 earthquakes with magnitudes up to 4.5 that occurred within the 161-km radius of the INL. The majority of earthquakes occurred in the Basin and Range Province surrounding the eastern Snake River Plain (ESRP). The largest of these earthquakes had a body-wave magnitude (mb) 4.5 and occurred on February 5, 2006. It was located northeast of Spencer, Idaho near the east-west trending Centennial fault along the Idaho-Montana border. The earthquake did not trigger SMAs located within INL buildings. Three earthquakes occurred within the ESRP, two of which occurred within the INL boundaries. One earthquake of coda magnitude (Mc) 1.7 occurred on October 18, 2006 and was located southeast of Pocatello, Idaho. The two earthquakes within the INL boundaries included the local magnitude (ML) 2.0 on July 31, 2006 located near the southern termination of the Lemhi fault and the Mc 0.4 on August 6, 2006 located near the center of INL. The ML 2.0 earthquake was well recorded by most of the INL seismic stations and had a focal depth of 8.98 km. First motions were used to compute a focal mechanism, which indicated normal faulting along one of two possible fault planes that may strike N76ºW and dip 70±3ºSW or strike N55ºW and dip 20±13ºNE. Slip along a normal fault that strikes N76ºW and dips 70±3ºSW is consistent with slip along a possible segment of the NW-trending Lemhi normal fault.
Date: September 1, 2007
Creator: Payne, S. J.; Carpenter, N. S.; Hodges, J. M. & Berg, R. G.
Partner: UNT Libraries Government Documents Department

Groundwater Monitoring and Field Sampling Plan for Operable Unit 10-08

Description: This plan describes the groundwater sampling and water level monitoring that will be conducted to evaluate contaminations in the Snake River Plain Aquifer entering and leaving the Idaho National Laboratory. The sampling and monitoring locations were selected to meet the data quality objectives detailed in this plan. Data for the Snake River Plain Aquifer obtained under this plan will be evaluated in the Operable Unit 10-08 Remedial Investigation/Feasibility Study report and will be used to support the Operable Unit 10-08 Sitewide groundwater model.
Date: May 1, 2007
Creator: Roddy, M. S.
Partner: UNT Libraries Government Documents Department

INL Seismic Monitoring Annual Report: January 1, 2010 – December 31, 2010

Description: During 2010, the INL Seismic Monitoring Program evaluated 11,606 earthquakes from around the world, the western United States, and local region of the eastern Snake River Plain (ESRP). INL located 2,085 earthquakes and man-made blasts within the local region outside and within a 161-km (or 100-mile) radius of INL. Of these events, 53 were small-to-moderate size earthquakes ranging in magnitude from 3.0 to 4.8. 672 earthquakes occurred within the 161-km radius of INL and the majority of these earthquakes were located in active regions of the Basin and Range Province that surrounds the ESRP. There were 10 microearthquakes within the boundary of the ESRP, all of magnitude less than or equal to 2.0. Five of those were located within and near the ESRP at Craters of the Moon National Monument (COM) at mid- and lower-crust depths and are interpreted to be related to fluid movement. Since 1972, INL has recorded 48 small-magnitude, microearthquakes (M = 2.2) within the ESRP (not including COM events) and 22 deep microearthquakes (M = 2.3) in the vicinity of Craters of the Moon National Monument.
Date: September 1, 2011
Creator: Carpenter, N. Seth; Payne, Suzette J.; Hodges, Jed M. & Berg, Robert G.
Partner: UNT Libraries Government Documents Department

INL Seismic Monitoring Annual Report: January 1, 2009 – December 31, 2009

Description: The Idaho National Laboratory (INL) has accumulated 37 years of earthquake data (1972-2009). This report covers the earthquake activity from January 1, 2009 through December 31, 2009 and is a continuation of previous annual reports on earthquake activity surrounding the eastern Snake River Plain (ESRP) and within and near the INL. It discusses the earthquake activity that has occurred around the local region and within a 161-km radius around the INL centered at 43? 39.00' N, 112? 47.00' W). It discusses the seismic station and strong motion accelerograph instrumentation used to record earthquake data and how they were analyzed. It also includes a brief discussion of continuous GPS (Global Positioning System) stations co-located at INL seismic stations.
Date: September 1, 2010
Creator: Carpenter, N. S.; Payne, S. J.; Hodges, J. M. & Berg, R. G.
Partner: UNT Libraries Government Documents Department

Results of 2001 Groundwater Sampling in Support of Conditional No Longer Contained-In Determination for the Snake River Plain Aquifer in the Vicinity of the INTEC at the INEEL

Description: This report summarizes the results of sampling five groundwater monitoring wells in the vicinity of the Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory in 2001. Information on general sampling practices, quality assurance practices, parameter concentrations, representativeness of sampling results, and cumulative cancer risk are presented. The information is provided to support a conditional No Longer Contained-In Determination for the Snake River Plain Aquifer in the vicinity of the Idaho Nuclear Technology and Engineering Center.
Date: April 1, 2002
Creator: Meachum, Teresa Ray
Partner: UNT Libraries Government Documents Department

INL Seismic Monitoring Annual Report: January 1, 2004 - December 31, 2004

Description: During 2004, INL analyzed more than 2,300 earthquakes. There were 487 earthquakes with magnitudes up to 4.0 located within the 161-km (100-mile) radius of the Idaho National Laboratory (INL). Seventeen small to moderate earthquakes of magnitudes from 3.0 to 5.0 occurred with the region outside the 161-km radius. Earthquakes activity occurred in areas that have experienced seismic activity in the past, the Basin and Range northwest of the INL, southwestern Montana, Yellowstone Park, Wyoming, Jackson, Wyoming, and southeastern Idaho. One earthquake was located northeast of Idaho Falls, Idaho within the eastern Snake River Plain (ESRP). No earthquakes were located within the INL boundaries. Earthquakes were not recorded by strong-motion accelerographs located in INL facilities.
Date: September 1, 2005
Creator: Payne, S.; Holland, A.; Hodges, J. & Berg, R.
Partner: UNT Libraries Government Documents Department

Investigation of groundwater flow paths through combined inversion of strontium isotope ratios and hydraulic head data. Final report

Description: Strontium (Sr) isotope and other geochemical data were collected for groundwater samples from the Snake River Plain aquifer in the vicinity of the Idaho National Engineering and Environmental Laboratory (INEEL). These geochemical data provide strong evidence for slow and fast groundwater flow zones that had not been previously characterized. The geochemical data were combined with existing hydraulic head data in groundwater flow and transport models. These models enable quantitative extraction of flow information from the data (i.e., inversion of the data). This new approach and the implications for INEEL environmental activities will be reported in two journal articles. One submitted recently and a second in preparation.
Date: December 4, 1999
Creator: Johnson, Thomas M.
Partner: UNT Libraries Government Documents Department

Characteristics and origin of Earth-mounds on the Eastern Snake River Plain, Idaho

Description: Earth-mounds are common features on the Eastern Snake River Plain, Idaho. The mounds are typically round or oval in plan view, <0.5 m in height, and from 8 to 14 m in diameter. They are found on flat and sloped surfaces, and appear less frequently in lowland areas. The mounds have formed on deposits of multiple sedimentary environments. Those studied included alluvial gravel terraces along the Big Lost River (late Pleistocene/early Holocene age), alluvial fan segments on the flanks of the Lost River Range (Bull Lake and Pinedale age equivalents), and loess/slopewash sediments overlying basalt flows. Backhoe trenches were dug to allow characterization of stratigraphy and soil development. Each mound has features unique to the depositional and pedogenic history of the site; however, there are common elements to all mounds that are linked to the history of mound formation. Each mound has a {open_quotes}floor{close_quotes} of a sediment or basement rock of significantly different hydraulic conductivity than the overlying sediment. These paleosurfaces are overlain by finer-grained sediments, typically loess or flood-overbank deposits. Mounds formed in environments where a sufficient thickness of fine-grained sediment held pore water in a system open to the migration to a freezing front. Heaving of the sediment occurred by the growth of ice lenses. Mound formation occurred at the end of the Late Pleistocene or early in the Holocene, and was followed by pedogenesis. Soils in the mounds were subsequently altered by bioturbation, buried by eolian deposition, and eroded by slopewash runoff. These secondary processes played a significant role in maintaining or increasing the mound/intermound relief.
Date: September 1, 1995
Creator: Tullis, J.A.
Partner: UNT Libraries Government Documents Department

Characterization of Contaminant Transport Using Naturally Occurring U-Series Disequilibria

Description: The main goal of the research is to understand the migratory behavior of radioactive contaminants in subsurface fractured systems by using naturally occurring U-series radionuclides as tracers under in-situ physico-chemical and hydrogeologic conditions. Naturally-occurring uranium- and thorium-series radioactive disequilibria can provide information on the rates of adsorption-desorption and transport of radioactive contaminants as well as on fluid transport and rock dissolution in a natural setting. This study will also provide an improved understanding of the hydrogeologic features of the site and their impact on the migration of radioactive contaminants. We intend to produce a realistic model of radionuclide migration in the Snake River Plain Aquifer beneath the INEEL by evaluating the retardation processes involved in the rock/water interaction. The major tasks are to (1) determine the natural distribution of U, Th, Pa and Ra isotopes in the groundwater as well as in rock minerals and sorbed phases, and (2) study rock/water interaction processes using U/Th series disequilibrium and a statistical analysis based model code for the calculation of in-situ retardation factors of radionuclides and rock/water interaction time scales.
Date: June 1, 1999
Creator: Murrell, Michael & Ku, Teh-Lung
Partner: UNT Libraries Government Documents Department

Groundwater ''fast paths'' in the Snake River plain aquifer: Radiogenic isotope ratios as natural groundwater tracers

Description: Preferential flow paths are expected in many groundwater systems and must be located because they can greatly affect contaminant transport. The fundamental characteristics of radiogenic isotope ratios in chemically evolving waters make them highly effective as preferential flow path indicators. These ratios tend to be more easily interpreted than solute-concentration data because their response to water-rock interaction is less complex. We demonstrate this approach with groundwater {sup 87}Sr/{sup 86}Sr ratios in the Snake River Plain aquifer within and near the Idaho National Engineering and Environmental Laboratory. These data reveal slow-flow zones as lower {sup 87}Sr/{sup 86}Sr areas created by prolonged interaction with the host basalts and a relatively fast flowing zone as a high {sup 87}Sr/{sup 86}Sr area.
Date: September 1, 2000
Creator: Johnson, Thomas M.; Roback, Robert C.; McLing, Travis L.; Bullen, Thomas D.; DePaolo, Donald J.; Doughty, Christine et al.
Partner: UNT Libraries Government Documents Department

Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plum Containment

Description: This report contains a summary of progress of only Dr. Crawford's part of the effort. This part of the overall project involves examination of the microbial genomics of the Snake River Plain Aquifer (SRPA) at the INEEL Test Area North (TAN) site. The work is being performed by two graduate students, Mr. Daniel Erwin and Ms. Amy Torguson. Progress is reported here as work done by each student.
Date: June 1, 2003
Creator: Crawford, Ronald L.
Partner: UNT Libraries Government Documents Department

Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment

Description: This is a collaborative project between the University of Idaho (Dr. Ronald L. Crawford, PI), the Idaho National Engineering and Environmental Laboratory (INEEL; Dr. Frederick Colwell, PI) and Northwind Environmental (Dr. Kent Sorenson, PI). This report contains a summary of progress of only Dr. Crawford's part of the effort. This part of the overall project involves examination of the microbial genomics of the Snake River Plain Aquifer (SRPA) at the INEEL Test Area North (TAN) site. The work is being performed by two graduate students, Mr. Daniel Erwin and Ms. Amy Torguson. Progress is reported here as work done by each student.
Date: June 1, 2003
Creator: Hirsch, Roland
Partner: UNT Libraries Government Documents Department

Chemical Constituents in Ground Water from 39 Selected Sites with an Evaluation of Associated Quality Assurance Data, Idaho National Engineering and Environmental Laboratory and Vicinity, Idaho

Description: This report presents a compilation of water-quality data along with an evaluation of associated quality assurance data collected during 1990-94 from the Snake River Plain aquifer and two springs located in areas that provide recharge to the Snake River Plain aquifer. The data were collected as part of the continuing hydrogeologic investigation at the Idaho National Engineering and Environmental Laboratory (INEEL). This report is the third in a series of four reports and presents data collected to quantitatively assess the natural geochemical system at the INEEL. Ground-water quality data - collected during 1990-94 from 39 locations in the eastern Snake River Plain - are presented.
Date: August 1, 1999
Creator: Knobel, L. L.; Bartholomay, R. C.; Tucker, B. J.; Williams, L. M. & Cecil, L. D.
Partner: UNT Libraries Government Documents Department

Radiochemical and Chemical Constituents in Water from Selected Wells and Springs from the Southern Boundary of the Idaho National Engineering and Environmental Laboratory to the Hagerman Area, Idaho, 1997

Description: The U.S. Geological Survey and the Idaho Department of Water Resources, in cooperation with the U.S. Department of Energy, sampled 18 sites as part of the fourth round of a long-term project to monitor water quality of the Snake River Plain aquifer from the southern boundary of the Idaho National Engineering and Environmental Laboratory to the Hagerman area. Water samples were collected and analyzed for selected radiochemical and chemical constituents. The samples were collected from seven domestic wells, six irrigation wells, two springs, one dairy well, one observation well, and one stock well. Two quality-assurance samples also were collected and analyzed. None of the radiochemical or chemical constituents exceeded the established maximum contaminant levels for drinking water. Many of the radionuclide- and inorganic-constituent concentrations were greater than their respective reporting levels.
Date: December 1, 1998
Creator: Bartholomay, R. C.; Williams, L. M. & Campbell, L. J.
Partner: UNT Libraries Government Documents Department

INEEL Subregional Conceptual Model Report Volume 3: Summary of Existing Knowledge of Natural and Anthropogenic Influences on the Release of Contaminants to the Subsurface Environment from Waste Source Terms at the INEEL

Description: This source-term summary document is intended to describe the current understanding of contaminant source terms and the conceptual model for potential source-term release to the environment at the Idaho National Engineering and Environmental Laboratory (INEEL), as presented in published INEEL reports. The document presents a generalized conceptual model of the sources of contamination and describes the general categories of source terms, primary waste forms, and factors that affect the release of contaminants from the waste form into the vadose zone and Snake River Plain Aquifer. Where the information has previously been published and is readily available, summaries of the inventory of contaminants are also included. Uncertainties that affect the estimation of the source term release are also discussed where they have been identified by the Source Term Technical Advisory Group. Areas in which additional information are needed (i.e., research needs) are also identified.
Date: September 1, 2003
Creator: Wichlacz, Paul L.
Partner: UNT Libraries Government Documents Department

GEOPHYSICAL INVESTIGATIONS OF THE ARCHAEOLOGICAL RESOURCES AT THE POWELL STAGE STATION

Description: Within the boundaries of the Idaho National Laboratory, an ongoing archaeological investigation of a late 19th century stage station was expanded with the use of Electro-Magnetic and Magnetic geophysical surveying. The station known as the Powell Stage Station was a primary transportation hub on the Snake River Plain, bridging the gap between railroad supply depots in Blackfoot, Idaho and booming mining camps throughout Central Idaho. Initial investigations have shown a strong magnetic signature from a buried road and previously unknown features that were not detected by visual surface surveys. Data gained from this project aids in federally directed cultural resource and land management and use requirements and has contributed additional information for archeological interpretation and cultural resource preservation.
Date: April 1, 2009
Creator: Gilbert, Hollie K.; Braun, Julie B.; Pace, Brenda R.; Heath, Gail & Scott, Clark
Partner: UNT Libraries Government Documents Department

Summary of Vadose -- Zone Conceptual Models for Flow and Contaminant Transport and 1999 - 2003 Progress on Resolving Deficiencies in Understanding the Vadose Zone at the INEEL

Description: The thick vadose zone that underlies the Idaho National Engineering and Environmental Laboratory has been recognized both as an avenue through which contaminants disposed at or near the ground surface can migrate to groundwater in the underlying Eastern Snake River Plain aquifer, and as a barrier to the movement of contaminants into the aquifer. Flow and contaminant transport in the vadose zone at the INEEL is complicated by the highly heterogeneous nature of the geologic framework and by the variations in the behavior of different contaminants in the subsurface. The state of knowledge concerning flow and contaminant transport in the vadose zone at and near the INEEL IN 1999 was summarized in Deficiencies in Vadose Zone Understanding at the Idaho National Engineering and Environmental Laboratory (Wood et al., 2000). These authors identified deficiencies in knowledge of flow and contaminant transport processes in the vadose zone, and provided recommendations for additional work that should be conducted to address these deficiencies. In the period since (Wood et al., 2000) was prepared, research has been published that, to some degree, address these deficiencies. This document provides a bibliography of reports, journal articles, and conference proceedings published 1999 through mid-2003 that are relevant to the vadose zone at or near the INEEL and provides a brief description of each work. Publications that address specific deficiencies or recommendations are identified, and pertinent information from selected publications is presented.
Date: December 1, 2003
Creator: Starr, Robert C.; Dettmers, Dana L.; Orr, Brennon R. & Wood, Thomas R.
Partner: UNT Libraries Government Documents Department

Prehistoric Rock Structures of the Idaho National Laboratory

Description: Over the past 13,500 years, human populations have lived in and productively utilized the natural resources offered by the cold desert environment of the northeastern Snake River Plain in eastern Idaho. Within an overall framework of hunting and gathering, groups relied on an intimate familiarity with the natural world and developed a variety of technologies to extract the resources that they needed to survive. Useful items were abundant and found everywhere on the landscape. Even the basaltic terrain and the rocks, themselves, were put to productive use. This paper presents a preliminary classification scheme for rock structures built on the Idaho National Laboratory landscape by prehistoric aboriginal populations, including discussions of the overall architecture of the structures, associated artifact assemblages, and topographic placement. Adopting an ecological perspective, the paper concludes with a discussion of the possible functions of these unique resources for the desert populations that once called the INL home.
Date: April 1, 2007
Creator: Pace, Brenda R
Partner: UNT Libraries Government Documents Department

A Source Water Assessment of the INEEL: Conjunctive Delineation of a Large Scale Area

Description: Presently, the INEEL operates and monitors 12 Public Water Systems that pump water from 22 wells for at the Site (Table 1). The source of water for each of these facilities is the eastern Snake River Plain aquifer. Because the INEEL operates Public Water Systems, it is required to conduct source water assessments for those facilities and to develop a Source Water Management Program.
Date: January 1, 2003
Creator: Sehlke, Gerald & Andersen, Bradley Don
Partner: UNT Libraries Government Documents Department

INL Seismic Monitoring Annual Report: January 1, 2008 – December 31, 2008

Description: During 2008, the INL Seismic Monitoring Program evaluated 7,284 earthquakes from around the world, the western United States, and local region of the eastern Snake River Plain. 2,396 earthquakes and man-made blasts were evaluated within the local region outside and within a 161-km (or 100-mile) radius of INL. Of these events, 25 were small to moderate size earthquakes ranging in magnitude from 3.0 to 3.9. 823 earthquakes occurred within the 161-km radius of INL and over 300 events were associated with eight different earthquake swarms which were located in active regions of the Basin and Range Province that surrounds the eastern Snake River Plain. Eight microearthquakes in 2008 of magnitude (M) 2.0 and less were located within the eastern Snake River Plain, seven at or near the Craters of the Moon National Monument and one within the INL boundary. Further analyses of the anomalously deep focal depths (15 to 42 km) and different waveform characteristics of all Craters of the Moon National Monument events (1999-2008) suggest association with magmatic processes. From 1972 to 2008, INL located 36 other small-magnitude microearthquakes (M < 2.0) at depths (< 11 km) within the eastern Snake River Plain and attributes these events to regional tectonic tensional stresses.
Date: September 1, 2009
Creator: Payne, S. J.; Carpenter, N. S.; Hodges, J. M. & Berg, R. G.
Partner: UNT Libraries Government Documents Department