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USGS Science Featured at Earth Science Conference
Released: 12/2/2005 6:45:35 AM

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From the 1906 San Francisco earthquake, recent unrest at Mount St. Helens, the environmental impacts of Hurricane Katrina, and the affects of our ever changing climate, scientists at the United States Geological Survey (USGS) will be presenting their research on these and many more topics at the American Geophysical Union (AGU) Fall Meeting at the Moscone West Convention Center in San Francisco, California, December 5-9. There is also a media trip on Sunday, December 4, by prior registration with the AGU press center.

SUNDAY, December 4

The 1906 Earthquake-Lessons Learned, Lessons Forgotten, and Future Directions: At the beginning of the 20th century, San Francisco was the "most cosmopolitan city outside of New York," the financial center of the west, and the eighth largest city in the country. Overnight, everything changed. Following a rousing performance by Caruso in Carmen the previous evening, the city was violently shaken awake at 5:12 a.m. on 18 April 1906. The 1906 magnitude 7.9 earthquake and resulting fire that raged over the next 3 days, San Francisco lay in rubble, devastated. There was also significant damage throughout northern California. More than 30,000 people lost their lives in San Francisco alone; 225,000 of the city’s 400,000 citizens were left homeless. The 2006 centennial recognition of this natural disaster that proved to be the birthplace of earthquake science in the United States, affords an opportunity to commemorate the cultural and social response to this historic event and to highlight a century of progress in understanding earthquake hazards and reducing the risks they pose. PUBLIC LECTURE by Mary Lou Zoback at Marriott Hotel, Yerba Buena, Salon 9, at 7:00 p.m.

MONDAY, December 5

Space-based Imaging of Water-level Changes Over Swamp Forests: Characterizing the temporal evolution of water-level changes can improve hydrological modeling predictions and enhance assessments of future flood hazards over wetlands. Using C-band (wavelength of 5.7 cm) European Remote Sensing Satellite (ERS) radar images, USGS scientists discovered that interferometric synthetic aperture radar (InSAR) images could maintain adequate coherence over swamp forests composed of moderately dense trees with a medium-low canopy closure in southeastern Louisiana to allow for measuring changes in water-level beneath tree cover with an unprecedented degree of vertical accuracy. C-band Radar Observes Water-level Change in Coastal Louisiana Swamp Forests; by Zhong Lu, Session H14B in MCC 3002 at 4:30 p.m.

TUESDAY, December 6

The Impact of Future San Francisco Bay Area Earthquakes: San Francisco Bay area earthquakes, much like major floods and hurricanes, have the potential for massive damage to dense urban population centers concentrated in vulnerable areas. The magnitude 7.9 San Francisco 1906 earthquake caused ground shaking intensities that were capable of damaging even modern, well-built structures, and the anticipated effects of a future major Bay area earthquake to lives, property, and infrastructure are comparable in scale to the damage caused by hurricane Katrina. Exposure to secondary hazards, such as the San Francisco fire and the New Orleans levee failure and flooding, greatly compounded the devastation in both disasters. A recent USGS study concluded that there is a 62% chance of one or more damaging earthquakes striking the greater San Francisco Bay area over the next 30 years. The USGS has prepared loss estimates for the 10 most likely forecast earthquake scenarios ranging in size from a magnitude 6.7 to a magnitude 7.9 repeat of the 1906 earthquake. Losses for a repeat of the 1906 quake are nearly double those predicted for a magnitude 6.9 rupture of the entire eastern Bay area Hayward fault. However, due to the high Hayward fault population density, an Association of Bay Area Governments study concluded that the two events would produce similar numbers of displaced households -- between 155,000-160,000 in the nine county Bay Area. Defining the scope of earthquake risk and exposure is a necessary step in developing long-term mitigation plans that include criteria for the evaluation and repair of damaged buildings, earthquake preparedness incentives, and increased public education about earthquake risk. When it happens again: impact of future San Francisco Bay area earthquakes; by Mary Lou Zoback, Session S23C in MCC: 3020 at 3:10 p.m.

WEDNESDAY, December 7

Volcanic Threat and Volcano Monitoring: A methodology for characterizing and ranking national volcanic threat was developed to prioritize improvements to volcano monitoring systems. Nearly 170 volcanoes in the U.S. and trust territories are ranked by level of threat based on a system of hazard factors such as explosivity, frequency of eruptions, and exposure factors such as nearby population and infrastructure, chosen to give a balanced view of unmitigated volcanic threat. The ranking of specific volcanoes in combined hazard scores are identified by region, broken into five threat groups ranging from very high to very low. Clearly, the higher-threat volcanoes warrant better early-warning monitoring capability than lower-threat volcanoes. Current monitoring capabilities are compared to the recommended level shown in the volcano’s threat score to determine volcanoes with significant "monitoring gaps". Further analysis identifies hazardous volcanoes where monitoring is inadequate for the threats posed, such as in many Cascade Range volcanoes. The analysis also highlights serious monitoring inadequacies in Alaska and the Northern Mariana Islands where the volcanic-ash hazard to aviation is a very high. Results of the volcanic threat assessment are being used to guide long-term improvements to volcano monitoring infrastructure operated by the USGS and various partners to establish a National Volcano Early Warning System. Assessing Volcanic Threat and Prioritizing Volcano Monitoring in the United States; by John Ewert Session V32A in MCC: 3009 at 10:50 a.m.

Types of active volcanoes have changed since the end of the ice age: first, it was the Kilauea type; lately, it’s been the Mt. St. Helens type: Volcanic systems are affected when the earth’s surface is subjected to great pressures caused by the buildup of thick ice sheets during ice ages, and again when those pressures are rapidly relieved as ice sheets melt at ice age’s end. Also, pressures on the sea floor change as the oceans partly "dry out" and recede, as they provide water vapor to make snow to feed the ice sheets, and again when oceans are refilled as ice ages end. To get information on changes in the types of volcanoes that are most active under different conditions of pressure loading of the earth’s crust and seafloors, USGS and Geological Survey of Japan scientists took advantage of the fact that a very rare element, indium, comes out in differing amounts in the plumes of different types of volcanoes. They measured indium in the layers of ice in Antarctica that correspond to snow that fell at different times during the last ice age, and after. The amounts of indium in the ice are very small, only about a hundredth of a part per quadrillion. Just after the ice age ended about ten thousand years ago, the most active volcanoes appear to have been of the basaltic type, which erupt in rivers of lava, such as those in Hawaii. But beginning about five thousand years ago, after the earth’s crust had time to "accustom" to the freedom from pressure from the ice sheets (and to the deeper, heavier oceans) a different type of volcano began to dominate, namely the explosively erupting kind of which Mount St. Helens in Washington is an example. POSTER PRESENTATION: Apparent mid-holocene change in types of degassing volcanoes, using indium in Antarctic ice as a tracer of volcanic source type; by Todd Hinkley & Akikazu Matsumoto, Session PP33C in MCC Level 2 at 1:40 p.m.

THURSDAY, December 8

Louisiana’s Wetlands, Going, Going...: The conversion of wetlands to open water occurs at alarming rates in coastal Louisiana. The value of wetlands for buffering storm surge and providing habitat has prompted efforts to identify and mitigate subsidence and other processes that cause wetland loss. How much is natural vs. human-induced is largely unknown but critical information for decisions about ongoing regional wetland restoration. We provide solutions for assessing maximum probable compaction rates at any site of interest where basic stratigraphic characteristics are known, allowing locations where subsidence is unlikely to be the result of sediment compaction alone to be identified. Numerical Constraints of Current Rates of Subsidence Due to Compaction of Shallow Sediments in the Louisiana Coastal Plain; by Tim Meckel, Session U41B in Marriott Salon 7 at 8:15 a.m.

Please note that this presentation has been rescheduled from Session G21D on Tuesday, December 6, at 9:15 a.m.

Exploring Radar Remote Sensing Technology for Coastal Studies: Using radar images from the European ENVISAT and ERS-2 satellites, USGS scientists developed a cross-platform interferometric synthetic aperture radar (InSAR) processing technique to generate InSAR images with a temporal separation of 30-minutes. This technique not only allows the exploration of data continuity from similar sensors but also enables the construction of high-resolution surface topography maps under favorable conditions. An exotic exploration of ENVISAT and ERS data continuity: 30-minute repeat pass InSAR over Southern Louisiana; by Zhong Lu, Session G41D in MCC 3005 at 9:15 a.m.

What’s Happening to Alaska’s Glaciers? Did you know that out of Alaska’s 2000 glaciers, more than 99% are now retreating or stagnating, and that Alaska’s glaciers now contribute more water to raising sea level than Antarctica and other polar areas? This glacial retreat involves a newly recognized process known as "disarticulation" at more than a dozen large, retreating Alaskan glaciers. This process, first observed at Bering Glacier, is the passive, rapid separation of large pieces of ice from the terminus of a thinning glacier, resulting in its rapid retreat. It occurs when a thinning glacier termini reaches a state of buoyancy and separates from its bed. Dozens of very large tabular icebergs have been observed separating in a single event. The results of disarticulation are very similar to those of the collapses observed at several Antarctic ice shelves. Repeated Rapid Retreats of Bering Glacier by Disarticulation - The Cyclic Dynamic Response of an Alaskan Glacier System; by Bruce F. Molnia, Session C42A in MCC 2002 at 10:50 a.m.

USGS Online Earthquake Hazard Maps: In May of 2005, following a review by the California Earthquake Prediction Evaluation Council, the USGS launched a new website that displays the probability of experiencing a Modified Mercalli Intensity VI earthquake in the next 24 hours. The forecast maps, based on a relatively simple application of earthquake magnitude relationships and associated principles, are primarily aimed at providing information related to earthquake aftershock hazards. Initial response to the system has been mostly positive but has required an increased effort toward educating the general public. This is particularly true with respect to communicating the important difference between an earthquake forecast and the common public conception of probability that’s associated with daily weather reports shown on a published and telecast maps. Initial interest in the web pages was very high with more than 700,000 individual visits during the first 4-6 weeks of operation; currently individual daily visits average around 3000 per day. USGS Online Short-term Hazard Maps: Experience in the First Year of Implementation; by Matthew Gerstenberger, Session S41D in MCC 3020 at 9:30 a.m.

FRIDAY, December 9

Global Water Availability in the Future: After examining a century of stream-flow measurements from 165 locations around the world, USGS scientists have a clearer picture of future global shifts in water availability. Simulations from an ensemble of 12 global climate models compared favorably with the historical stream-flow data, lending credibility to the same models’ stream-flow forecasts for the coming decades. And what do the models show about the future? The models predict 10 to 40 percent increases in runoff in eastern equatorial Africa and in high latitude North America and Eurasia by the year 2050. They also predict 10 to 30 percent decreases in runoff in southern Africa, southern Europe, the Middle East and mid-latitude western North America by 2050. Changes in sustainable water availability could have considerable regional-scale consequences for human health, economic activity, ecosystem function and geophysical processes. 20th- and 21st-Century Changes in Stream flow Associated with Global Warming; by Paul C. Milly, Session H51I in MCC 3004 at 8:20 a.m.

Volcano Dancing: Different Rhythms and Diverse Styles: Using interferometric synthetic aperture radar (InSAR), a technique that is capable of measuring ground-surface deformation with centimeter to sub centimeter precision and spatial resolution of tens-of-meters over relatively large regions, USGS scientists mapped the diverse deformation patterns and studied the associated magma supply mechanisms for volcanoes along the Aleutian Arc. The studies demonstrate that InSAR can improve our understanding on how the Aleutian Volcanoes work and enhance our capability to predict future eruptions and associated hazards. InSAR Imaging of Volcanic Deformation Over Aleutian Islands; by Zhong Lu, Session G52A in MCC 3005, at 11:20 a.m.

Sediment in the Chesapeake Bay Watershed: Fine-grained sediment is having an adverse effect on the living resources and habitat of the Chesapeake Bay and its watershed. To reduce sediment inputs to the Bay, it is necessary to quantify erosion rates and sediment yields and identify the significant sources of fine-grained sediment. This research identifies major tributaries that are significant contributors of sediment, such as the Susquehanna, which carries an average 1 million tons of sediment per year as it approaches the Bay. In selected sub basins of the major tributaries, the ’sediment fingerprinting’ approach is being used to identify whether the channel banks or upland areas, such as cropland, are major sources. Sediment Yields and Sediment Sources in the Chesapeake Bay Watershed; by Allen Gellis Session H54A in MCC 3004 at 5 p.m.


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