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At least 73 records · Page 4Linked to original sources
USGS2011

Mars atmospheric surface interactions and the CO2 cycle

Mars' northern and southern seasonal polar caps are formed during their respective autumn and winter seasons both by condensation of atmospheric carbon dioxide (CO 2 ) directly onto the surface, and through atmospheric precipitation in the form of CO 2 snow. During the polar spring and summer, the seasonal ice sublimes, returning CO 2 to the atmosphere. Roughly 25% of the atmosphere, which is 95% CO 2 by volume, is cycled through the seasonal caps annually. This CO 2 cycle dominates atmospheric circulation on Mars and must be thoroughly understood before the fundamental questions about Mars' climate history and the global distribution of near‐surface water can be addressed.

Eos, Transactions, American Geophysical Union↗
USGS2011

Survey explores active tectonics in northeastern Caribbean

There is renewed interest in studying the active and complex northeastern Caribbean plate boundary to better understand subduction zone processes and for earthquake and tsunami hazard assessments [e.g., ten Brink and Lin , 2004; ten Brink et al ., 2004; Grindlay et al ., 2005]. To study the active tectonics of this plate boundary, the GEOPRICO-DO (Geological, Puerto Rico-Dominican) marine geophysical cruise, carried out between 28 March and 17 April 2005 (Figure 1), studied the active tectonics of this plate boundary. Initial findings from the cruise have revealed a large underwater landslide, and active faults on the seafloor (Figures 2a and 2c). These findings indicate that the islands within this region face a high risk from tsunami hazards, and that local governments should be alerted in order to develop and coordinate possible mitigation strategies.

Eos, Transactions, American Geophysical Union↗
USGS2011

Implementing a U.S. national phenology network

The passing of seasons, as gauged by annual events or phenophases in organisms' life cycles, is arguably one of the most pervasive environmental variations on Earth. Shifts in seasonal timing, or phenology, are observed in flowering and other stages of plant development, animal migration and reproduction, hibernation, and the seasonal activity of cold-blooded animals [e.g., Schwartz , 2003; Root et al ., 2005]. As an important life history trait, phenology is an object of natural selection; depending on timescales, shifts in phenology can lead to evolutionary change. Thus, phenology is not only an indicator of pattern in environmental science, but also its variation has fitness consequences for individuals, and these can scale up to broader ecological dynamics.

Eos, Transactions, American Geophysical Union↗
USGS2011

Sensor web enables rapid response to volcanic activity

Rapid response to the onset of volcanic activity allows for the early assessment of hazard and risk [ Tilling , 1989]. Data from remote volcanoes and volcanoes in countries with poor communication infrastructure can only be obtained via remote sensing [ Harris et al. , 2000]. By linking notifications of activity from ground-based and spacebased systems, these volcanoes can be monitored when they erupt. Over the last 18 months, NASA's Jet Propulsion Laboratory (JPL) has implemented a Volcano Sensor Web (VSW) in which data from ground-based and space-based sensors that detect current volcanic activity are used to automatically trigger the NASA Earth Observing 1 (EO-1) spacecraft to make highspatial-resolution observations of these volcanoes.

Eos, Transactions, American Geophysical Union↗
USGS2011

New products from the shuttle radar topography mission

New data products with broad applicability to the Earth sciences are now available from the Shuttle Radar Topography Mission (SRTM). SRTM, a joint project of the National Geospatial-Intelligence Agency (NGA) and NASA, flew aboard the Space Shuttle Endeavour on an 11-day mission in February 2000 with the goal of collecting a near-global data set of high-resolution elevation data [ Fan and Kobrick , 2000]. Data from the mission have been available to researchers for several years, but newly available products offer enhanced usability and applicability. Final products include elevation data resulting from a substantial editing effort by the NGA in which water bodies and coastlines were well defined and data artifacts known as spikes and wells (single pixel errors) were removed. This second version of the SRTM data set, also referred to as ‘finished’ data, represents a significant improvement over earlier versions that had nonflat water bodies, poorly defined coastlines, and numerous noise artifacts. The edited data are available at a one-arc-second resolution (approximately 30 meters) for the United States and its territories, and at a three-arc-second resolution (approximately 90 meters) for non-U.S. areas.

Eos, Transactions, American Geophysical Union↗
USGS2011

Linking middle-school teachers to Earthscope

EarthScope is a multidisciplinary geophysical investigation of the structure and deformation of the North American continent. Components include a transportable array of digital seismometers (USArray) that will image the continental crust and underlying mantle, and Global Positioning System (GPS) receivers and strainmeters (Plate Boundary Observatory, PBO) that will measure tectonic and volcanic deformations Translating geophysics for kindergarten through 12th grade (K‐12) teachers and their students involves inviting them to explore new understandings of how Earth works. When they construct their understanding of Earth science through geophysical problem solving, these learners can engage in Earth‐Scope, which offers unprecedented public access to data from seismology and geodesy.

Eos, Transactions, American Geophysical Union↗
USGS2011

Giant sand waves at the mouth of San Francisco Bay

A field of giant sand waves, among the largest in the world, recently was mapped in high resolution for the first time during a multibeam survey in 2004 and 2005 through the strait of the Golden Gate at the mouth of San Francisco Bay in California (Figure la). This massive bed form field covers an area of approximately four square kilometers in water depths ranging from 30 to 106 meters, featuring more than 40 distinct sand waves with crests aligned approximately perpendicular to the dominant tidally generated cross-shore currents, with wavelengths and heights that measure up to 220 meters and 10 meters, respectively. Sand wave crests can be traced continuously for up to two kilometers across the mouth of this energetic tidal inlet, where depth-averaged tidal currents through the strait below the Golden Gate Bridge exceed 2.5 meters per second during peak ebb flows. Repeated surveys demonstrated that the sand waves are active and dynamic features that move in response to tidally generated currents. The complex temporal and spatial variations in wave and tidal current interactions in this region result in an astoundingly diverse array of bed form morphologies, scales, and orientations. Bed forms of approximately half the scale of those reported in this article previously were mapped inside San Francisco Bay during a multibeam survey in 1997 [Chin et al., 1997].

California↗
USGS2011

Gas hydrate transect across northern Cascadia margin

Gas hydrate is a solid compound mainly comprised of methane and water that is stable under low temperature and high pressure conditions. Usually found in offshore environments with water depths exceeding about 500 meters and in arctic regions associated with permafrost, gas hydrates form an efficient storage system for natural gas. Hence, they may represent an important future energy resource [e.g., Kvenvolden , 1988]. Gas hydrates also form a natural geo‐hazard, and may play a significant role in global climate change [e.g., Dillon et al. , 2001].

Eos, Transactions, American Geophysical Union↗
USGS2011

The reawakening of Alaska's Augustine volcano

Augustine volcano, in south central Alaska, ended a 20-year period of repose on 11 January 2006 with 13 explosive eruptions in 20 days. Explosive activity shifted to a quieter effusion of lava in early February, forming a new summit lava dome and two short, blocky lava flows by late March (Figure 1). The eruption was heralded by eight months of increasing seismicity, deformation, gas emission, and small phreatic eruptions, the latter consisting of explosions of steam and debris caused by heating and expansion of groundwater due to an underlying heat source.

Alaska↗
USGS2007

Understanding Merapi-type volcanoes

"We have to understand volcano science to know what to monitor.” That simple statement by Antonius Ratdomopurbo, director of the Indonesian Center for Volcano Technology [Balai Penyelidikan dan Pengembangan‐Teknologi (BPPTK)],captured the spirit and content of a recent workshop about Merapi and Merapi‐type volcanoes. Merapi still is experiencing low levels of unrest, following a peak in eruptive activity on 14 June 2006, when pyroclastic flows swept into the evacuated village of Kali Adem and killed two workers who refused to leave. The volcano is an essential element that underlies life in Yogyakarta, Indonesia: It is a constant reminder of the perilous beauty as well as the mystical stature of volcanoes in Indonesia, the world's most volcanically active country. It also is a proving ground for new technologies and monitoring methods in volcano hazards.

Eos, Transactions, American Geophysical Union↗
USGS2007

Mount St. Helens Petrology Workshop

Following seismic activity in late September 2004, the current eruption of Mount St. Helens began with an explosive steam and ash emission on 1 October 2004, with hot dacite emerging from the crater floor on 11 October 2004. Nearly two years later, with more than 80 million cubic meters of erupted dacite, accompanied by rare explosions and predominantly shallow seismicity questions still remain about what initiated and what is sustaining the eruption. The U.S. Geological Survey's (USGS) Cascade Volcano Observatory (CVO) hosted the 2006 Mount St. Helens Petrology Workshop in Vancouver, Wash., on 27–30 August 2006. With many of the more than 40 workshop participants finalizing contributions to a USGS Professional Paper on the current Mount St. Helens eruption, the workshop was a timely opportunity to share results, reconcile interpretations, and plan future research.

Washington↗
USGS2007

Hazards from hydrothermally sealed volcanic conduits

The 17 March 2006 eruption from Raoul Island (Kermadec arc, north of New Zealand) is interpreted as a magmatic‐hydrothermal event triggered by shaking associated with a swarm of local earthquakes. The eruption, which tragically claimed the life of New Zealand Department of Conservation Ranger Mark Kearney, occurred without significant volcanic seismicity or any of the precursory responses the volcanic hydrothermal system exhibited prior to a similarly sized eruption in 1964. Preliminary evidence suggests that the absence of precursory behavior is probably the consequence of hydrothermal sealing of the volcanic conduit since the 1964 eruption, and points to potential hazards associated with quiescent oceanic island volcanoes.

Eos, Transactions, American Geophysical Union↗
USGS2007

Sea level rise in Tampa Bay

Understanding relative sea level (RSL) rise during periods of rapid climatic change is critical for evaluating modern sea level rise given the vulnerability of Antarctic ice shelves to collapse [ Hodgson et al, 2006], the retreat of the world's glaciers [ Oerlemans, 2005], and mass balance trends of the Greenland ice sheet [ Rignot and Kanagaratnam, 2006]. The first-order pattern of global sea level rise following the Last Glacial Maximum (LGM, ∼21,000 years ago) is well established from coral [ Fairbanks, 1989], continental shelf [ Hanebuth et al, 2000], and other records [ Pirazzoli, 2000] and has been integrated into a global ICE-5G model of glacio-isostatic adjustment (GIA) [ Peltier, 2004]. However, uncertainty introduced by paleo water depth of sea level indicators, radiocarbon chronology (i.e., reservoir corrections for marine shell dates), postglacial isostatic adjustment, and other processes affecting vertical position of former shorelines produces scatter in RSL curves, limiting our knowledge of sea level rise during periods of rapid glacial decay. One example of this limitation is the Gulf of Mexico/Florida region where, despite decades of study, RSL curves produce two conflicting patterns: those showing progressive submergence with a decelerating rate during the past 5000 years [ Scholl et al, 1969] and those showing high sea level during the middle of the Holocene [ Blum et al, 2001; Balsillie and Donoghue, 2004], where the Holocene represents a geologic epoch that extends from about 10,000 years ago to present times. This discrepancy is emblematic of the uncertainty surrounding Holocene sea level and ice volume history in general.

Florida↗
USGS2007

Impact of recent extreme Arizona storms

Heavy rainfall on 27–31 July 2006 led to record flooding and triggered an historically unprecedented number of debris flows in the Santa Catalina Mountains north of Tucson, Ariz. The U.S. Geological Survey (USGS) documented record floods along four watercourses in the Tucson basin, and at least 250 hillslope failures spawned damaging debris flows in an area where less than 10 small debris flows had been documented in the past 25 years. At least 18 debris flows destroyed infrastructure in the heavily used Sabino Canyon Recreation Area (http://wwwpaztcn.wr.usgs.gov/rsch_highlight/articles/20061 l.html). In four adjacent canyons, debris flows reached the heads of alluvial fans at the boundary of the Tucson metropolitan area. While landuse planners in southeastern Arizona evaluate the potential threat of this previously little recognized hazard to residents along the mountain front, an interdisciplinary group of scientists has collaborated to better understand this extreme event.

Arizona↗
USGS2007

Evolving plans for the USA National Phenology Network

Phenology is the study of periodic plant and animal life cycle events, how these are influenced by seasonal and interannual variations in climate, and how they modulate the abundance, diversity, and interactions of organisms. The USA National Phenology Network (USA-NPN) is currently being organized to engage federal agencies, environmental networks and field stations, educational institutions, and citizen scientists. The first USA-NPN planning workshop was held August 2005, in Tucson, Ariz. (Betancourt et al. [2005]; http://www.uwm.edu/Dept/Geography/npn/; by 1 June 2007, also see http://www.usanpn.org). With sponsorship from the U.S. National Science Foundation, the U.S. Geological Survey (USGS), the U.S. Fish and Wildlife Service, and NASA, the second USA-NPN planning workshop was held at the University of Wisconsin-Milwaukee on 10–12 October 2006 to (1) develop lists of target species and observation protocols; (2) identify existing networks that could comprise the backbone of nationwide observations by 2008; (3) develop opportunities for education, citizen science, and outreach beginning in spring 2007; (4) design strategies for implementing the remote sensing component of USA-NPN; and (5) draft a data management and cyberinfrastructure plan.

Eos, Transactions, American Geophysical Union↗
USGS2007

Law of the sea, the continental shelf, and marine research

The question of the amount of seabed to which a coastal nation is entitled is addressed in the United Nations Convention on the Law of the Sea (UNCLOS). This treaty, ratified by 153 nations and in force since 1994, specifies national obligations, rights, and jurisdiction in the oceans, and it allows nations a continental shelf out to at least 200 nautical miles or to a maritime boundary. Article 76 (A76) of the convention enables coastal nations to establish their continental shelves beyond 200 nautical miles and therefore to control, among other things, access for scientific research and the use of seabed resources that would otherwise be considered to lie beyond national jurisdiction. To date, seven submissions for extended continental shelves (ECS) have been filed under UNCLOS (Table 1). These submissions have begun to define the ambiguities in A76. How these ambiguities are resolved into final ECS boundaries will probably set important precedents guiding the future delimitation of the ECS by the United States, which has not ratified the convention, and other coastal nations. This report uses examples from the first three submissions—by the Russian Federation, Brazil, and Australia—to identify outstanding issues encountered in applying A76 to ECS delimitation.

Eos, Transactions, American Geophysical Union↗
USGS2007

Alvin explores the deep northern Gulf of Mexico Slope

Many of the world's productive deepwater hydrocarbon basins experience significant and ongoing vertical migration of fluids and gases to the modern seafloor. These products, which are composed of hydrocarbon gases, crude oil, formation fluids, and fluidized sediment, dramatically change the geologic character of the ocean floor, and they create sites where chemosynthetic communities supported by sulfide and hydrocarbons flourish. Unique fauna inhabit these sites, and the chemosynthetic primary production results in communities with biomass much greater than that of the surrounding seafloor.

Gulf of Mexico↗