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The term “landslide trigger” refers to an external stimulus, such as intense rainfall, rapid snowmelt, seismic shaking, volcanic eruption, stream/coastal erosion, or natural dam failure, which causes an immediate or near-immediate response in the form of landslide activity. In this paper, we discuss the types of landslides caused by these triggering processes and present a limited number of worldwide examples of their occurrence.
A main degradation product of Irgarol [2-(methylthio)-4-(tert-butylamino)-6-(cyclopropylamino)-s-triazine], one of the most widely used compounds in antifouling paints, was detected at trace levels in seawater and sediment samples collected from several marinas on the Mediterranean coast. This degradation product was identified as 2-methylthio-4-tert-butylamino-s-triazine. The unequivocal identification of this compound in seawater samples was carried out by solid-phase extraction (SPE) coupled on-line with liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS). SPE was carried out by passing 150 ml of seawater sample through a cartridge containing a polymeric phase (PLRP-s), with recoveries ranging from 92 to 108% (n=5). Using LC-MS detection in positive ion mode, useful structural information was obtained by increasing the fragmentor voltage, thus permitting the unequivocal identification of this compound in natural samples. Method detection limits were in the range of 0.002 to 0.005 ??g/l. Overall, the combination of on-line SPE and LC-APCI-MS represents an important advance in environmental analysis of herbicide degradation products in seawater, since it demonstrates that trace amounts of new polar metabolites may be determined rapidly. This paper reports the LC-MS identification of the main degradation product of Irgarol in seawater and sediment samples. ?? 2001 Elsevier Science B.V. All rights reserved.
From the Landsat program's inception in 1972 to the present, the earth science user community has benefited from a historical record of remotely sensed data. The multispectral data from the Landsat 5 (L5) Thematic Mapper (TM) sensor provide the backbone for this extensive archive. Historically, the radiometric calibration procedure for this imagery used the instrument's response to the Internal Calibrator (IC) on a scene-by-scene basis to determine the gain and offset for each detector. The IC system degraded with time causing radiometric calibration errors up to 20 percent. In May 2003 the National Landsat Archive Production System (NLAPS) was updated to use a gain model rather than the scene acquisition specific IC gains to calibrate TM data processed in the United States. Further modification of the gain model was performed in 2007. L5 TM data that were processed using IC prior to the calibration update do not benefit from the recent calibration revisions. A procedure has been developed to give users the ability to recalibrate their existing Level-1 products. The best recalibration results are obtained if the work order report that was originally included in the standard data product delivery is available. However, many users may not have the original work order report. In such cases, the IC gain look-up table that was generated using the radiometric gain trends recorded in the NLAPS database can be used for recalibration. This paper discusses the procedure to recalibrate L5 TM data when the work order report originally used in processing is not available. A companion paper discusses the generation of the NLAPS IC gain and bias look-up tables required to perform the recalibration.
Treatment with caustic chemicals typically is used to increase pH and decrease concentrations of dissolved aluminum, iron, and/or manganese in largevolume, metal-laden discharges from active coal mines. Generally, aluminum and iron can be removed effectively at near-neutral pH (6 to 8), whereas active manganese removal requires treatment to alkaline pH (~10). The treatment cost depends on the specific chemical used (NaOH, CaO, Ca(OH) 2 , Na 2 CO 3 , or NH 3 ) and increases with the quantities of chemical added and sludge produced. The pH and metals concentrations do not change linearly with the amount of chemical added. Consequently, the amount of caustic chemical needed to achieve a target pH and the corresponding effluent composition and sludge volume can not be accurately determined without empirical titration data or the application of geochemical models to simulate the titration of the discharge water with caustic chemical(s). The AMDTreat computer program (http://amd.osmre.gov/ ) is widely used to compute costs for treatment of coal-mine drainage. Although AMDTreat can use results of empirical titration with industrial grade caustic chemicals to compute chemical costs for treatment of net-acidic or net-alkaline mine drainage, such data are rarely available. To improve the capability of AMDTreat to estimate (1) the quantity and cost of caustic chemicals to attain a target pH, (2) the concentrations of dissolved metals in treated effluent, and (3) the volume of sludge produced by the treatment, a titration simulation is being developed using the geochemical program PHREEQC (wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/) that will be coupled as a module to AMDTreat. The simulated titration results can be compared with or used in place of empirical titration data to estimate chemical quantities and costs. This paper describes the development, evaluation, and potential utilization of the PHREEQC titration module for AMDTreat.
Determining sediment thickness and delineating bedrock topography are important for assessing groundwater availability and characterizing contamination sites. In recent years, the horizontal-to-vertical spectral ratio (HVSR) seismic method has emerged as a non-invasive, cost-effective approach for estimating the thickness of unconsolidated sediments above bedrock. Using a three-component seismometer, this method uses the ratio of the average horizontal- and vertical-component amplitude spectrums to produce a spectral ratio curve with a peak at the fundamental resonance frequency. The HVSR method produces clear and repeatable resonance frequency peaks when there is a sharp contrast (>2:1) in acoustic impedance at the sediment/bedrock boundary. Given the resonant frequency, sediment thickness can be determined either by (1) using an estimate of average local sediment shear-wave velocity or by (2) application of a power-law regression equation developed from resonance frequency observations at sites with a range of known depths to bedrock. Two frequently asked questions about the HVSR method are (1) how accurate are the sediment thickness estimates? and (2) how much do sediment thickness/bedrock depth estimates change when using different published regression equations? This paper compares and contrasts different approaches for generating HVSR depth estimates, through analysis of HVSR data acquired in the vicinity of Tylerville, Connecticut, USA.
Geospatial Artificial Intelligence (GeoAI) increasingly relies on automated analysis of authoritative geospatial data, exposing limitations in data infrastructures originally designed for simple dissemination rather than for knowledge-driven use. From the perspective of scientific spatial data providers, the challenge is enabling GeoAI responsibly while retaining semantic clarity, provenance, reproducibility, and governance. This short paper (i) examines how GeoAI exposed limitations within existing geospatial data infrastructures, and (ii) identifies provider-side requirements for an authoritative knowledge infrastructure. Drawing on GIScience, scientific workflow, and operational AI literature, the paper outlines implications for national mapping organizations that seek to support advanced analytics without jeopardizing scientific rigor or stewardship responsibilities.
Little is known of the incidence and pathogenic effects of infectious and parasitic diseases in the world's 15 crane species. in addition to being a primary cause of crane morality, diseases increase the susceptibility of an animal to depredation, malnutrition, accidents, and other mortality factors and reduces its chances of survival during times of stress. Although the treatment and control of diseases of wild cranes is difficult, the management of captive cranes is becoming more and more successful through the use of intensive husbandry, preventative medicine, and parasite control programs. this paper describes some of the infectious and parasitic diseases of wild and captive cranes and outlines management principles for their control, especially in confinement.
The U. S. Geological Survey has a requirement for the collection of large amounts of digital map data from existing graphic map separates. Prototype production techniques have been developed to capture line data from the map separates using a raster-scanning input device. After minimal editing in raster form, the data are converted to 'unstructured' vector form. In order to be processed further, the line data must be topologically structured (nodes identified and start-node, end-node, area-left, and area-right tags associated with each line-segment chain). This paper describes the techniques which have been developed at the U. S. Geological Survey to topologically structure the raster-scanned line map data.
A review is given on the geological aspects of carbonate beaches that a geologist thinks may be useful for an engineer. Though, Geologists not involved in engineering problems may find it difficult to know what an engineer should understand about carbonate beaches. Nevertheless, there are at least eleven topics that are potentially very useful for engineers to keep in mind. This paper emits the discussions of certain kinds of carbonate shorelines that are beyond the scope of engineering issues, and focuses on sand-sized coastal carbonate deposits.
TSU in partnership with the USGS has conducted extensive research regarding biode??gradation of contaminants in karst aquifers. This research resulted in the development of a numerical approach to modeling biodegradation of contaminants in karst aquifers that is taught to environmental engineering students in several steps. First, environmental engineering students are taught chemical-reaction engineering principles relating to a wide variety of environmental fate and transport issues. Second, as part of TSU's engineering course curriculum, students use a non-ideal flow laboratory reactor system and run a tracer study to establish residence time distribution (RTD). Next, the students couple that formula to a first-order biodegradation rate and predict the removal of a biodegradable contaminant as a function of residence time. Following this, students are shown data collected from karst bedrock wells that suggest that karst aquifers are analogous to non-ideal flow reactors. The students are challenged to develop rates of biodegradation through lab studies and use their results to predict biodegradaton at an actual contaminated karst site. Field studies are also conducted to determine the accuracy of the students' predictions. This academic approach teaches biodegradation processes, rate-kinetic processes, hydraulic processes and numerical principles. The students are able to experience how chemical engineering principles can be applied to other situations, such as, modeling biodegradation of contaminants in karst aquifers. This paper provides background on the chemical engineering principles and karst issues used in the research-enhanced curriculum. ?? American Society for Engineering Education, 2006.
Unprecedented demand on coastal resources in the 1980's has generated a need for valid information and analyses to support wise management of the coastal zone. The National Coastal Ecosystems Team of the U.S. Fish and Wildlife Service recently implemented a geographic information system to enhance its ability to analyze and display environmental information about the coastal zone. Outputs from this system have been presented to the State of Louisiana Senate and House Committees on Natural Resources and to the Congressional House of Representatives Committee on Merchant Marine and Fisheries. The purpose of this paper is to describe the use of the Map Overlay Statistical System for addressing selected coastal issues and to discuss its utility for coastal decisionmaking.
The Woodrow Wilson Bridge on I-495 over the Potomac River in Prince Georges County, Maryland is being replaced. Physical local scour model studies for the proposed piers for the new bridge were performed in order to help establish design scour depths. Tests were conducted in two different flumes, one in the USGS-BRD Conte Research Center in Turners Falls, Massachusetts and one in the FHWA Turner Fairbanks Laboratory in McLean, Virginia. Due to space limitations in this publication only the tests conducted in the USGS flume are presented in this paper. Two different pier designs were tested. One of the piers was also tested with two different diameter dolphin systems. Copyright ASCE 2004.
A general problem in combining road vector data with orthoimagery from different sources is that they rarely align. There are a variety of causes to this problem, but the most common one is that the latest products are collected with higher accuracy and improved processing techniques. In previous work, we developed techniques to automatically correct the alignment of vector data with orthoimagery using a technique called conflation. However, in applying our technique to real-world datasets provided by USGS, we discovered that these techniques failed in some areas. In this paper, we describe some refinements to our original approach that provide consistently better results in aligning the vector data with the orthoimagery.
Recently, new identification methods have been developed by using the concept of optimal-recursive filtering and stochastic approximation. These methods, known as stochastic identification, are based on the statistical properties of the signal and noise, and do not require the assumptions of current methods. The criterion for stochastic system identification is that the difference between the recorded output and the output from the identified system (i.e., the residual of the identification) should be equal to white noise. In this paper, first a brief review of the theory is given. Then, an application of the method is presented by using ambient vibration data from a nine-story building.
Techniques for the hydraulic restoration of placer-mined streams and floodplains were developed in Denali National Park and Preserve, Alaska. The two-year study at Glen Creek focused on a design of stream and floodplain geometry using hydraulic capacity and shear stress equations. Slope and sinuosity values were based on regional relationships. Design requirements included a channel capacity for a bankfull discharge and a floodplain capacity for a 1.5- to 100-year discharge. Several bio-engineering techniques using alder and willow, including anchored brush bars, streambank hedge layering, seedlings, and cuttings, were tested to dissipate floodwater energy and encourage sediment deposition until natural revegetation stabilized the new floodplains. Permanently monumented cross-sections installed throughout the project site were surveyed every one to three years. Nine years after the project began, a summer flood caused substantial damage to the channel form, including a change in width/depth ratio, slope, and thalweg location. Many of the alder brush bars were heavily damaged or destroyed, resulting in significant bank erosion. This paper reviews the original hydraulic design process, and describes changes to the channel and floodplain geometry over time, based on nine years of cross-section surveys.
Interferometric synthetic aperture radar (InSAR) imaging is a recently developed geodetic technique capable of measuring ground-surface deformation with centimeter to subcentimeter vertical precision and spatial resolution of tens-of-meter over a relatively large region (/spl sim/10/sup 4/ km/sup 2/). The spatial distribution of surface deformation data, derived from InSAR images, enables the construction of detailed mechanical models to enhance the study of magmatic and tectonic processes associated with volcanoes. This paper summarizes our recent InSAR studies of several Alaska volcanoes, which include Okmok, Akutan, Kiska, Augustine, Westdahl, and Peulik volcanoes.
Researchers from the U.S. Geological Survey (USGS) Woods Hole Coastal and Marine Science Center (WHCMSC), in collaboration with Coastal Carolina University (CCU) and University of South Carolina (USC), conducted a scientific field study to investigate the ocean circulation and sediment transport processes offshore of Fire Island, NY. Although the physical processes along the entire linear extent of Fire Island (~50 km) are of interest to the project, one particular region of focus is at the western end of the island where offshore sand ridges out to depths of 20 m extend across the inner shelf and connect to the near-shore bar system. The primary objective was to measure the physical processes around the sand ridges, including circulation patterns, wave parameters, bottom stress, and suspended sediment. Transects of instrumentation were positioned along and across the crests and troughs of the ridge field. A site at the top of a ridge and a site at the bottom of an adjacent trough were each populated with two tripods designed to provide high-resolution measurements near the sea-bed to record sediment re-suspension events. Measurements at these two sites include near bottom velocity profiles, acoustic Doppler velocimeters, pressure, optical transmission and backscatter at high sampling rates. Other measurements include upward looking velocity profiles, temperature, salinity, sonar images and profiles, and sediment size classes. Five smaller tripods were deployed to complete lines alongshore and across shore over a 5 km area to provide a regional picture. These tripods recorded upward looking velocity profiles and near bottom temperature, pressure and salinity. Surface buoys marked the position of the tripods and collected surface measurements at six of the sites. One buoy gathered meteorological measurements. The sites were occupied from January to April, 2012. This deployment was similar to previous efforts off Cape Hatteras, NC, in 2009, and is part of an ongoing effort to understand regional patterns in circulation and sediment transport and the interaction of inner shelf and near shore processes. New instrumentation for the USGS was introduced, including a variety of current and wave measurement equipment, acquisition and telemetry in near-realtime of the weather data, time series sonar imaging equipment, and anti-fouling wipers. Preliminary results suggest a complex and subtle relationship between wind and across shore current velocity in this region, and a more straightforward relationship between winds and alongshore currents. This paper also includes a preliminary report on the effectiveness of new measurement techniques used during this experiment.
The thematic mapper (TM) sensor aboard Landsats 4, 5 and enhanced TM plus (ETM+) on Landsat 7 collect imagery at 30-m sample distance in six spectral bands. New with ETM+ is a 15-m panchromatic (P) band. With image sharpening techniques, this higher resolution P data, or as an alternative, the 10-m (or 5-m) P data of the SPOT satellite, can increase the spatial resolution of the multispectral (MS) data. Sharpening requires that the lower resolution MS image be coregistered and resampled to the P data before high spatial frequency information is transferred to the MS data. For visual interpretation and machine classification tasks, it is important that the sharpened data preserve the spectral characteristics of the original low resolution data. A technique was developed for sharpening (in this case, 3:1 spatial resolution enhancement) visible spectral band data, based on a model of the sensor system point spread function (PSF) in order to maintain spectral fidelity. It combines high-pass (HP) filter sharpening methods with iterative image restoration to reduce degradations caused by sensor-system-induced blurring and resembling. Also there is a spectral fidelity requirement: sharpened MS when filtered by the modeled degradations should reproduce the low resolution source MS. Quantitative evaluation of sharpening performance was made by using simulated low resolution data generated from digital color-IR aerial photography. In comparison to the HP-filter-based sharpening method, results for the technique in this paper with simulated data show improved spectral fidelity. Preliminary results with TM 30-m visible band data sharpened with simulated 10-m panchromatic data are promising but require further study.