Transient deterministic shallow landslide modeling: Requirements for susceptibility and hazard assessments in a GIS framework   总被引：12，自引：0，他引：12  

J.W. Godt  R.L. Baum  W.Z. Savage  D. Salciarini  W.H. Schulz  E.L. Harp 《Engineering Geology》2008,102(3-4):214

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On flares,substorms, and the theory of impulsive flux transfer events     

A. Bratenahl  P. J. Baum 《Solar physics》1976,47(1):345-360

Solar flares and magnetospheric substorms are discussed in the context of a general theory of impulsive flux transfer events (IFTE). IFTE theory, derived from laboratory observations in the Double Inverse Pinch Device (DIPD), provides a quantitative extension of neutral sheet theories to include nonsteady field line reconnection. Current flow along the reconnection line increases with magnetic flux storage. When flux build-up exceeds the level corresponding to a critical limit on the current, instabilities induce a sudden transition in the mode of conduction. The resulting IFTE, indifferent to the specific modes and instabilities involved, is the more energetic, the lower the initial resistivity. It is the more violent, the greater the resulting resistivity increase and the faster its growth. Violent events can develop very large voltage transients along the reconnection line. Persistent build-up promoting conditions produce relaxation oscillations in the quantity of flux and energy stored (build-up-IFTE cycles). It is difficult to avoid the conclusion: flares and substorms are examples of IFTE.  相似文献   

Effect of antecedent-hydrological conditions on rainfall triggering of debris flows in ash-fall pyroclastic mantled slopes of Campania (southern Italy)     

E. Napolitano  F. Fusco  R. L. Baum  J. W. Godt  P. De Vita 《Landslides》2016,13(5):967-983

Mountainous areas surrounding the Campanian Plain and the Somma-Vesuvius volcano (southern Italy) are among the most risky areas of Italy due to the repeated occurrence of rainfall-induced debris flows along ash-fall pyroclastic soil-mantled slopes. In this geomorphological framework, rainfall patterns, hydrological processes taking place within multi-layered ash-fall pyroclastic deposits and soil antecedent moisture status are the principal factors to be taken into account to assess triggering rainfall conditions and the related hazard. This paper presents the outcomes of an experimental study based on integrated analyses consisting of the reconstruction of physical models of landslides, in situ hydrological monitoring, and hydrological and slope stability modeling, carried out on four representative source areas of debris flows that occurred in May 1998 in the Sarno Mountain Range. The hydrological monitoring was carried out during 2011 using nests of tensiometers and Watermark pressure head sensors and also through a rainfall and air temperature recording station. Time series of measured pressure head were used to calibrate a hydrological numerical model of the pyroclastic soil mantle for 2011, which was re-run for a 12-year period beginning in 2000, given the availability of rainfall and air temperature monitoring data. Such an approach allowed us to reconstruct the regime of pressure head at a daily time scale for a long period, which is representative of about 11 hydrologic years with different meteorological conditions. Based on this simulated time series, average winter and summer hydrological conditions were chosen to carry out hydrological and stability modeling of sample slopes and to identify Intensity-Duration rainfall thresholds by a deterministic approach. Among principal results, the opposing winter and summer antecedent pressure head (soil moisture) conditions were found to exert a significant control on intensity and duration of rainfall triggering events. Going from winter to summer conditions requires a strong increase of intensity and/or duration to induce landslides. The results identify an approach to account for different hazard conditions related to seasonality of hydrological processes inside the ash-fall pyroclastic soil mantle. Moreover, they highlight another important factor of uncertainty that potentially affects rainfall thresholds triggering shallow landslides reconstructed by empirical approaches.  相似文献   

Uncertain human consequences in asteroid risk analysis and the global catastrophe threshold     

Seth D. Baum 《Natural Hazards》2018,94(2):759-775

This paper studies the risk of collision between asteroids and Earth. It focuses on uncertainty in the human consequences of asteroid collisions, with emphasis on the possibility of global catastrophe to human civilization. A detailed survey of the asteroid risk literature shows that while human consequences are recognized as a major point of uncertainty, the studies focus mainly on physical and environmental dimensions of the risk. Some potential human consequences are omitted entirely, such as the possibility of asteroid explosions inadvertently causing nuclear war. Other human consequences are modeled with varying degrees of detail. Direct medical effects are relatively well-characterized, while human consequences of global environmental effects are more uncertain. The latter are evaluated mainly in terms of a global catastrophe threshold, but such a threshold is deeply uncertain and may not even exist. To handle threshold uncertainty in asteroid policy, this paper adapts the concept of policy boundaries from literature on anthropogenic global environmental change (i.e., planetary boundaries). The paper proposes policy boundaries of 100 m asteroid diameter for global environmental effects and 1 m for inadvertent nuclear war. Other policy implications include a more aggressive asteroid risk mitigation policy and measures to avoid inadvertent nuclear war. The paper argues that for rare events like large asteroid collisions, the absence of robust data means that a wide range of possible human consequences should be considered. This implies humility for risk analysis and erring on the side of caution in policy.  相似文献   

When hazard avoidance is not an option: lessons learned from monitoring the postdisaster Oso landslide,USA     

Reid  Mark E.  Godt  Jonathan W.  LaHusen  Richard G.  Slaughter  Stephen L.  Badger  Thomas C.  Collins  Brian D.  Schulz  William H.  Baum  Rex L.  Coe  Jeffrey A.  Harp  Edwin L.  Schmidt  Kevin M.  Iverson  Richard M.  Smith  Joel B.  Haugerud  Ralph A.  George  David L. 《Landslides》2021,18(9):2993-3009

On 22 March 2014, a massive, catastrophic landslide occurred near Oso, Washington, USA, sweeping more than 1 km across the adjacent valley flats and killing 43 people. For the following 5 weeks, hundreds of workers engaged in an exhaustive search, rescue, and recovery effort directly in the landslide runout path. These workers could not avoid the risks posed by additional large-scale slope collapses. In an effort to ensure worker safety, multiple agencies cooperated to swiftly deploy a monitoring and alerting system consisting of sensors, automated data processing and web-based display, along with defined communication protocols and clear calls to action for emergency management and search personnel. Guided by the principle that an accelerating landslide poses a greater threat than a steadily moving or stationary mass, the system was designed to detect ground motion and vibration using complementary monitoring techniques. Near real-time information was provided by continuous GPS, seismometers/geophones, and extensometers. This information was augmented by repeat-assessment techniques such as terrestrial and aerial laser scanning and time-lapse photography. Fortunately, no major additional landsliding occurred. However, we did detect small headscarp failures as well as slow movement of the remaining landslide mass with the monitoring system. This was an exceptional response situation and the lessons learned are applicable to other landslide disaster crises. They underscore the need for cogent landslide expertise and ready-to-deploy monitoring equipment, the value of using redundant monitoring techniques with distinct goals, the benefit of clearly defined communication protocols, and the importance of continued research into forecasting landslide behavior to allow timely warning.

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Temporal trends in abundance of fish in the tidal Delaware River     

Stephen B. Weisberg  Peter Himchak  Tom Baum  Harold T. Wilson  Russell Allen 《Estuaries and Coasts》1996,19(3):723-729

Water quality in the tidal Delaware River has improved dramatically over the last several decades. Areas near Philadelphia that were once anoxic and formed a pollution block to migratory fish passage now rarely experience dissolved oxygen concentrations less than 3 ppm. To assess whether these improvements in water quality led to increased abundance of juvenile fishes, data from a beach seine survey conducted annually since 1980 were examined. The number of species captured increased throughout the tidal river, but the increase was greatest in the areas downstream of Philadelphia, wheare water quality has improved the most. Abundance of juvenile striped bass and American shad, two important game species in the river whose migratory patterns make them susceptible to water quality problems, both increased more than, 1,000-fold during the last decade. Correlatations between the temporal abundance patterns of these species in the tidal Delaware River and in other East Coast systems were poor, suggesting that increases in their numbers were related more closely to improving conditions within the Delaware than to factors affecting coastal stocks.  相似文献   

Tektonische Untersuchungen am Westrand der Eifeler Nord-Süd-Zone zwischen Untermaubach und Heimbach     

Fritz Baum 《International Journal of Earth Sciences》1955,44(1):148-167

Zusammenfassung Die Abbiegung der SE-Flanke des Vennsattels zum Westrand der Eifeler N-S-Zone wird von einem Störungsbündel begleitet, das die Achsenflexur zu einem Staffelbruch fortbildete und mehrmals posthum in Tätigkeit trat. Methoden werden entwickelt, um aus der Verstellung der feintektonischen Elemente nicht sichtbare Verwerfungen zu erschließen.  相似文献   

Erratum to: Early warning of rainfall-induced shallow landslides and debris flows in the USA     

Rex L. Baum  Jonathan W. Godt 《Landslides》2010,7(3):387-272

The state of knowledge and resources available to issue alerts of precipitation-induced landslides vary across the USA. Federal and state agencies currently issue warnings of the potential for shallow, rapidly moving landslides and debris flows in a few areas along the Pacific coast and for areas affected by Atlantic hurricanes. However, these agencies generally lack resources needed to provide continuous support or to expand services to other areas. Precipitation thresholds that form the basis of landslide warning systems now exist for a few areas of the USA, but the threshold rainfall amounts and durations vary over three orders of magnitude nationwide and over an order of magnitude across small geographic areas such as a county. Antecedent moisture conditions also have a significant effect, particularly in areas that have distinct wet and dry seasons. Early warnings of shallow landslides that include specific information about affected areas, probability of landslide occurrence, and expected timing are technically feasible as illustrated by a case study from the Seattle, WA area. The four-level warning scheme (Null, Outlook, Watch, Warning) defined for Seattle is based on observed or predicted exceedance of a cumulative precipitation threshold and a rainfall intensity–duration threshold combined with real-time monitoring of soil moisture. Based on analysis of historical data, threshold performance varies according to precipitation characteristics, and threshold exceedance corresponds to a given probability of landslide occurrence. Experience in Seattle during December 2004 and January 2005 illustrates some of the challenges of providing landslide early warning on the USA West Coast.  相似文献   

A NICMOS imaging study of high-z quasar host galaxies     

Marek J. Kukula  James S. Dunlop  Ross J. McLure  Lance Miller  Will J. Percival  Stefi A. Baum  Christopher P. O'Dea 《Monthly notices of the Royal Astronomical Society》2001,326(4):1533-1546

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A Direct Image of the Inner Torus of NGC 1068     

J.F. Gallimore  S.A. Baum  C.P. O'Dea 《Astrophysics and Space Science》1997,248(1-2):253-260

We present the first VLBI observations of the compact source S1 in the radio jet of NGC 1068. Roughly 1 pc in length and 0.2 pc wide, S1 resolves into clumps aligned perpendicular to the local radio jet axis. The radio continuum emission arises from a hot (Te ~ 106 K), dense (ne ~ 106 cm-3) plasma, and the source of the radio emission is either thermal free-free emission or Thomson-reflected synchrotron emission. The clouds comprising S1 are opaque to soft X-radiation, and we therefore propose that S1 is the inner, ionized region, or ‘hot zone,’ of the obscuring medium surrounding the active nucleus. The covering fraction of the hot zone is small, Cf ⋦ 10%. Since the covering fraction of the dusty, obscuring medium is probably much larger, the obscuring disk must either flare or warp outside of the hot zone. That the radio jet and hot zone axes are perpendicular also suggests that the hot zone may be considered to trace the outermost extent of the accretion disk. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献