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At least 145 records · Page 8Linked to original sources
USGS2011

New episodes of volcanism at Kilauea Volcano, Hawaii

Mid‐2007 was a time of intense activity at Kilauea Volcano, Hawaii (see Figure 1). In June, the long‐lived Pu'u 'Ō'ō—Kupaianaha eruption, a dual‐vent system along the east rift zone (ERZ) that has been erupting since 1983 [Heliker et al., 2003], paused due to the outbreak of a new vent farther up the rift (see Figure 2). The Pu'u 'Ō'ō vent collapsed following that activity, and the resulting reorganization of the magma plumbing system led to the formation of a second new eruptive vent 2 kilometers downrift of Pu'u 'Ō'ō. These events were well documented by geological, geophysical, and geochemical monitoring. This article summarizes results from these monitoring efforts and interprets the changes that have occurred at Kilauea since June 2007.

Hawaii↗
USGS2011

New global hydrography derived from spaceborne elevation data

To study the Earth system and to better understand the implications of global environmental change, there is a growing need for large-scale hydrographic data sets that serve as prerequisites in a variety of analyses and applications, ranging from regional watershed and freshwater conservation planning to global hydrological, climate, biogeochemical, and land surface modeling. Yet while countless hydrographic maps exist for well-known river basins and individual nations, there is a lack of seamless high-quality data on large scales such as continents or the entire globe. Data for many large international basins are patchy, and remote areas are often poorly mapped. In response to these limitations, a team of scientists has developed data and created maps of the world's rivers that provide the research community with more reliable information about where streams and watersheds occur on the Earth's surface and how water drains the landscape. The new product, known as HydroSHEDS (Hydrological Data and Maps Based on Shuttle Elevation Derivatives at Multiple Scales), provides this information at a resolution and quality unachieved by previous global data sets, such as HYDRO1k [ U.S. Geological Survey (USGS) , 2000].

Eos, Transactions, American Geophysical Union↗
USGS2011

Small explosion from new vent at Kilauea’s summit

At 0258 Hawaii‐Aleutian Standard Time (HST) on 19 March 2008, a small explosion scattered altered and fresh lithic debris across a 40‐hectare area at the summit of Kilauea volcano. This explosion, the first recorded there since 1924, issued from a vent about 35 meters wide along the east wall of Halema'uma'u Crater. Ballistic fragments—the largest measuring nearly 1 meter across—were propelled upward more than 70 meters onto the Halema'uma'u crater rim. Coarse ash and centimeter‐size lithic debris covered part of Crater Rim Drive, and fine ash was deposited farther than 30 kilometers to the southwest.

Hawaii↗
USGS2011

Alaska's Pavlof volcano ends 11-year repose

After an 11‐year period of repose, Pavlof volcano on the Alaska Peninsula (Figure 1) began an episode of Strombolian eruption lasting 31 days, from 14 August to 13 September 2007. The eruption began abruptly on 14 August after a minor increase in seismicity the previous day. Nearly continuous lava fountaining, explosions, and lahars caused by minor disruption of the ice and snow cover on the volcano characterized the eruption. The eruption also produced diffuse ash plumes that reached 5–6 kilometers above sea level, but the plumes were too small and did not extend high enough to affect local or regional air travel. Melting of snow and ice on the upper part of the edifice by hot debris avalanches and lava resulted in numerous lahars that entered the sea and inundated a 2×10 6 square meter area on the volcanos southern slope.

Eos, Transactions, American Geophysical Union↗
USGS2011

Development of pan-Arctic database for river chemistry

More than 10% of all continental runoff flows into the Arctic Ocean. This runoff is a dominant feature of the Arctic Ocean with respect to water column structure and circulation. Yet understanding of the chemical characteristics of runoff from the pan-Arctic watershed is surprisingly limited. The Pan- Arctic River Transport of Nutrients, Organic Matter, and Suspended Sediments ( PARTNERS) project was initiated in 2002 to help remedy this deficit, and an extraordinary data set has emerged over the past few years as a result of the effort. This data set is publicly available through the Cooperative Arctic Data and Information Service (CADIS) of the Arctic Observing Network (AON). Details about data access are provided below.

Eos, Transactions, American Geophysical Union↗
USGS2011

Initial fluvial response to the removal of Oregon's Marmot Dam

A temporary, 14‐meter‐high earthen cofferdam standing in place of Marmot Dam was breached on 19 October 2007, allowing the 80‐ kilometer‐long Sandy River to flow freely from Mount Hood, Oreg., to the Columbia River for the first time in nearly 100 years. Marmot Dam is one of the largest dams in the western United States (in terms of height and volume of stored sediment) to have been removed in the past 40 years, and its removal exposed approximately 730,000 cubic meters of stored sand and gravel to erosion and transport by the newly energetic mountain river. At the time, its breach represented the greatest release of sediment from any U.S. dam removal. (The March 2008 breaching of Montana's Milltown Dam exposed about 5–10 times as much sediment to potential erosion.)

Oregon↗
USGS2011

Land management in the Anthropocene: Is history still relevant?

Ecological restoration, conservation, and land management are often based on comparisons with reference sites or time periods, which are assumed to represent “natural” or “properly functioning” conditions. Such reference conditions can provide a vision of the conservation or management goal and a means to measure progress toward that vision. Although historical ecology has been used successfully to guide resource management in many parts of the world, the continuing relevance of history is now being questioned. Some scientists doubt that lessons from the past can inform management in what may be a dramatically different future, given profound climate change, accelerated land use, and an onslaught of plant and animal invasions.

Conference Paper↗
USGS2011

Recent extreme avalanches: Triggered by climate change?

On 25 September 2008, seismo meters operated by the Alaska Volcano Observatory (AVO) registered strong ground shaking. On the basis of previous experience with such large seismic signals, AVO personnel were able to rapidly identify the seismic event as an avalanche. Two days later, an AVO overflight of Iliamna volcano, near Alaska's Cook Inlet, confirmed that a massive chunk of glacial ice and rock had broken free from its position on the upper flanks of the volcano, generating a massive avalanche that could have buried an entire town had it occurred in a more populated area. Rapidly moving rock, ice, or debris avalanches, such as the one that occurred on Iliamna, can be highly destructive and deadly. Similar events have caused the deaths of hundreds to thousands of people [ Keefer and Larsen, 2007]. In general, avalanches that move more than 1 million cubic meters of material are rare. However, a remarkable series of large avalanches recently occurred in Alaska and the Caucasus, providing a new opportunity to better understand this type of hazard. All events initiated in steep mountain slopes, involved rock and significant amounts of ice, and traveled for 10–35 kilometers.

Eos, Transactions, American Geophysical Union↗
USGS2011

Illuminating Northern California’s Active Faults

Newly acquired light detection and ranging (lidar) topographic data provide a powerful community resource for the study of landforms associated with the plate boundary faults of northern California (Figure 1). In the spring of 2007, GeoEarthScope, a component of the EarthScope Facility construction project funded by the U.S. National Science Foundation, acquired approximately 2000 square kilometers of airborne lidar topographic data along major active fault zones of northern California. These data are now freely available in point cloud (x, y, z coordinate data for every laser return), digital elevation model (DEM), and KMZ (zipped Keyhole Markup Language, for use in Google EarthTM and other similar software) formats through the GEON OpenTopography Portal (http://www.OpenTopography.org/data). Importantly, vegetation can be digitally removed from lidar data, producing high-resolution images (0.5- or 1.0-meter DEMs) of the ground surface beneath forested regions that reveal landforms typically obscured by vegetation canopy (Figure 2)

California↗
USGS2011

Eruption of Alaska volcano breaks historic pattern

In the late morning of 12 July 2008, the Alaska Volcano Observatory (AVO) received an unexpected call from the U.S. Coast Guard, reporting an explosive volcanic eruption in the central Aleutians in the vicinity of Okmok volcano, a relatively young (~2000-year-old) caldera. The Coast Guard had received an emergency call requesting assistance from a family living at a cattle ranch on the flanks of the volcano, who reported loud "thunder," lightning, and noontime darkness due to ashfall. AVO staff immediately confirmed the report by observing a strong eruption signal recorded on the Okmok seismic network and the presence of a large dark ash cloud above Okmok in satellite imagery. Within 5 minutes of the call, AVO declared the volcano at aviation code red, signifying that a highly explosive, ash-rich eruption was under way.

Alaska↗
USGS2011

Online interactive U.S. Reservoir Sedimentation Survey Database

In April 2009, the U.S. Geological Survey and the Natural Resources Conservation Service (prior to 1994, the Soil Conservation Service) created the Reservoir Sedimentation Survey Database (RESSED) and Web site, the most comprehensive compilation of data from reservoir bathymetric and dry basin surveys in the United States. RESSED data can be useful for a number of purposes, including calculating changes in reservoir storage characteristics, quantifying rates of sediment delivery to reservoirs, and estimating erosion rates in a reservoir's watershed.

Eos, Transactions, American Geophysical Union↗
USGS2011

The unexpected awakening of Chaitén Volcano, Chile

On 2 May 2008, a large eruption began unexpectedly at the inconspicuous Chaitén volcano in Chile's southern volcanic zone. Ash columns abruptly jetted from the volcano into the stratosphere, followed by lava dome effusion and continuous low-altitude ash plumes [ Lara , 2009]. Apocalyptic photographs of eruption plumes suffused with lightning were circulated globally. Effects of the eruption were extensive. Floods and lahars inundated the town of Chaitén, and its 4625 residents were evacuated. Widespread ashfall and drifting ash clouds closed regional airports and cancelled hundreds of domestic flights in Argentina and Chile and numerous international flights [ Guffanti et al. , 2008]. Ash heavily affected the aquaculture industry in the nearby Gulf of Corcovado, curtailed ecotourism, and closed regional nature preserves. To better prepare for future eruptions, the Chilean government has boosted support for monitoring and hazard mitigation at Chaitén and at 42 other highly hazardous, active volcanoes in Chile.

Chaiten↗