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M. Murray

Publications and source records attributed to M. Murray.

9 recordsLinked to original sources
USGS2012

Deformation from 1973 through 1991 in the epicentral area of the 1992 Landers, California, Earthquake (Ms = 7.5)

Deformation of a 50 × 60 km trilateration network that spans the epicenter of the 1992 Landers earthquake( M s = 7.5) was measured by seven surveys over the 19 years preceding the earthquake. Three moderate earthquakes (1979 Homestead Valley, M s = 5.6; 1986 North Palm Springs, M s = 6.0; and 1992 Joshua Tree, M s = 6.1) occurred within the network during those 19 years. Here we use geodetic and seismic data to construct a dislocation model for each of the three moderate earthquakes. Coseismic changes due to these three moderate earthquakes as predicted by the dislocation models are then removed from the trilateration data. The residual geodetic changes appear to be uniform in time. We take those changes to represent secular strain accumulation. This strain accumulation clearly shows right‐lateral shear across the San Andreas fault but also suggests a northwest‐southeast extension northeast of the eastern end of the “Big Bend” of the San Andreas fault. The Landers earthquake ruptured along a north‐northwest trend across this region of northwest‐southeast extension.

California↗
USGS2012

Variations of transcript profiles between sea otters Enhydra lutris from Prince William Sound, Alaska, and clinically normal reference otters

Development of blood leukocyte gene transcript profiles has the potential to expand condition assessments beyond those currently available to evaluate wildlife health, including sea otters Enhydra lutris , both individually and as populations. The 10 genes targeted in our study represent multiple physiological systems that play a role in immuno-modulation, inflammation, cell protection, tumor suppression, cellular stress-response, xenobiotic metabolizing enzymes, and antioxidant enzymes. These genes can be modified by biological, physical, or anthropogenic impacts and consequently provide information on the general type of stressors present in a given environment. We compared gene transcript profiles of sea otters sampled in 2008 among areas within Prince William Sound impacted to varying degrees by the 1989 ‘Exxon Valdez’ oil spill with those of captive and wild reference sea otters. Profiles of sea otters from Prince William Sound showed elevated transcription in genes associated with tumor formation, cell death, organic exposure, inflammation, and viral exposure when compared to the reference sea otter group, indicating possible recent and chronic exposure to organic contaminants. Sea otters from historically designated oiled areas within Prince William Sound 19 yr after the oil spill had higher transcription of genes associated with tumor formation, cell death, heat shock, and inflammation than those from areas designated as less impacted by the spill.

Alaska↗
USGS2001

Representation of natural vegetation in protected areas: Capturing the geographic range

Current conservation strategies for plant and animal species rarely address the need to protect the species throughout its geographic range thereby capturing potential genetic and ecological variation. We examined the degree that existing protected areas in the western United States satisfied this goal for four widespread vegetation cover types. We used latitude and longitude to stratify the distribution of these types into 16 cells, each of which was further stratified by up to five elevation classes. While protection of some vegetation types was high in parts of their range, it was minimal to nonexistent in other parts. While it is yet to be shown that protecting a given species throughout its geographic range is essential for its long-term existence, in the face of often unpredictable environmental changes, it seems a prudent course to follow. Our results suggest that if full range protection is a conservation goal, the existing network of protected areas may be inadequate for the task.

Biodiversity and Conservation↗
USGS2000

January 30, 1997 eruptive event on Kilauea Volcano, Hawaii, as monitored by continuous GPS

A continuous Global Positioning System (GPS) network on Kilauea Volcano captured the most recent fissure eruption in Kilauea's East Rift Zone (ERZ) in unprecedented spatial and temporal detail. The short eruption drained the lava pond at Pu'u O' o, leading to a two month long pause in its on-going eruption. Models of the GPS data indicate that the intrusion's bottom edge extended to only 2.4 km. Continuous GPS data reveal rift opening 8 hours prior to the eruption. Absence of precursory summit inflation rules out magma storage overpressurization as the eruption's cause. We infer that stresses in the shallow rift created by the continued deep rift dilation and slip on the south flank decollement caused the rift intrusion.

Geophysical Research Letters↗
USGS1996

Water resources data, Florida, water year 1995. Volume 2A: South Florida - surface water

Water resources data for 1995 water year in Florida consists of continuous or daily discharge for 314 streams, periodic discharge for 37 streams, continuous or daily stage for 55 streams, periodic stage for 12 streams, peak discharge for 12 streams, and peak stage for 12 streams; continuous or daily elevations for 30 lakes, periodic elevations for 73 lakes; continuous ground-water levels for430 wells, periodic ground-water levels for2,095 wells; quality of water data for 165 surface-water sites and 246 wells. The data for South Florida included continuous or daily discharge for 73 streams, continuous or daily stage for 76 streams, peak stage discharge for no streams, continuous elevation for 1 lake; continuous groundwater levels for 222 wells, periodic ground-water levels for 772 wells and no miscellaneous water-level measurements; quality-of-water for 29 surface-water sites and 207 wells. The data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

Florida↗
USGS1994

The magnitude 6.7 Northridge, California, earthquake of 17 January 1994

The most costly American earthquake since 1906 struck Los Angeles on 17 January 1994. The magnitude 6.7 Northridge earthquake resulted from more than 3 meters of reverse slip on a 15-kilometer-long south-dipping thrust fault that raised the Santa Susana mountains by as much as 70 centimeters. The fault appears to be truncated by the fault that broke in the 1971 San Fernando earthquake at a depth of 8 kilometers. Of these two events, the Northridge earthquake caused many times more damage, primarily because its causative fault is directly under the city. Many types of structures were damaged, but the fracture of welds in steel-frame buildings was the greatest surprise. The Northridge earthquake emphasizes the hazard posed to Los Angeles by concealed thrust faults and the potential for strong ground shaking in moderate earthquakes.

Los Angeles↗
USGS1994

Water resources data, Florida, water year 1993. Volume 2A: South Florida - surface water

Water resources data for 1993 water year in Florida consists of continuous or daily discharge for 312 streams, periodic discharge for 9 streams, miscellaneous discharge for 107 streams, continuous or daily stage for 91 streams, periodic stage for 0 streams, peak discharge for 30 streams, continuous daily tide stage for 9 streams, and peak stage for 21 streams, continuous or daily elevations for 41 lakes, periodic elevations for 73 lakes; continuous ground-water levels for 406 wells, periodic ground-water levels for 569 wells, and miscellaneous water level measurements for 1,860 wells; quality of water data for 109 surface-water sites and 642 wells. The data for South Florida included continuous or daily discharge for 75 streams, continuous or daily stage for 54 streams, peak stage discharge for 1 stream, continuous elevation for 1 lake; continuous ground-water levels for 203 wells, periodic ground-water levels for 299 wells and miscellaneous water-level measurements for 462 well; quality-of-water for 3 surface-water sites and 545 wells. The data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

Florida↗
USGS1993

The Cape Mendocino, California, earthquakes of April 1992: Subduction at the triple junction

The 25 April 1992 magnitude 7.1 Cape Mendocino thrust earthquake demonstrated that the North America—Gorda plate boundary is seismogenic and illustrated hazards that could result from much larger earthquakes forecast for the Cascadia region. The shock occurred just north of the Mendocino Triple Junction and caused strong ground motion and moderate damage in the immediate area. Rupture initiated onshore at a depth of 10.5 kilometers and propagated up-dip and seaward. Slip on steep faults in the Gorda plate generated two magnitude 6.6 aftershocks on 26 April. The main shock did not produce surface rupture on land but caused coastal uplift and a tsunami. The emerging picture of seismicity and faulting at the triple junction suggests that the region is likely to continue experiencing significant seismicity.

California↗