SEARCH · Search USGS

Results for “Landslides”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources

USGS2012

Monitoring subsurface hydrologic response for precipitation-induced shallow landsliding in the San Francisco Bay area, California, USA

Intense winter storms in the San Francisco Bay area (SFBA) of California, USA often trigger shallow landslides. Some of these landslides mobilize into potentially hazardous debris flows. A growing body of research indicates that rainfall intensity-duration thresholds are insufficient for accurate prediction of landslide occurrence. In response, we have begun long-term monitoring of the hydrologic response of land-slide-prone hillslopes to rainfall in several areas of the SFBA. Each monitoring site is equipped with sensors for measuring soil moisture content and piezometric pressure at several soil depths along with a rain gauge connected to a cell phone or satellite telemetered data logger. The data are transmitted in near-real-time, providing the ability to monitor hydrologic conditions before, during, and after storms. Results are guiding the establishment of both antecedent and storm-specific rainfall and moisture content thresholds which must be achieved before landslide-causative positive pore water pressures are generated. Although widespread shallow landsliding has not yet occurred since the deployment of the monitoring sites, several isolated land-slides have been observed in the area of monitoring. The landslides occurred during a period when positive pore water pressures were measured as a result of intense rainfall that followed higher-than-average season precipitation totals. Continued monitoring and analysis will further guide the establishment of more general-ized thresholds for different regions of the SFBA and contribute to the development and calibration of physi-cally-based predictive models.

Conference Paper↗

USGS2021

Principles for collaborative risk communication: Reducing landslide losses in Puerto Rico

Landslides are frequent and damaging natural hazards that threaten the people and the natural and built environments of Puerto Rico. In 2017, more than 70,000 landslides were triggered across the island by heavy rainfall from Hurricane María, prompting requests by local professionals for landslide education and outreach materials. This article describes a novel collaborative risk communication framework that was developed to meet those requests and shaped the creation of a Spanish- and English-language Landslide Guide for Residents of Puerto Rico. Collaborative risk communication is defined here as an iterative process guided by a set of principles for the interdisciplinary coproduction of hazards information and communication products by local and external stakeholders. The process that supports this form of risk communication involves mapping out the risk communication stakeholders in the at-risk or disaster-affected location—in this case Puerto Rico—and collaborating over time to address a shared challenge, such as landslide hazards. The approach described in this article involved the formation of a core team of government and university partners that expanded in membership to conduct collaborative work with an informal network of hazards professionals from diverse sectors in Puerto Rico. The following principles guided this process: cultural competence, ethical engagement, listening, inclusive decision making, empathy, convergence research, nested mentoring, adaptability, and reciprocity. This article contributes to the field of risk communication and emergency management by detailing these principles and the associated process in order to motivate collaborative risk communication efforts in different geographic and cultural contexts. While the work described here focuses on addressing landslides, the principles and process are transferable to other natural, technological, and willful human-caused hazards. They may also serve as a roadmap for future partnerships among government agencies and university researchers to inform the cocreation of science education and outreach tools.

Puerto Rico↗

USGS2007

Hazard assessment of the Tidal Inlet landslide and potential subsequent tsunami, Glacier Bay National Park, Alaska

An unstable rock slump, estimated at 5 to 10 × 10 6 m 3 , lies perched above the northern shore of Tidal Inlet in Glacier Bay National Park, Alaska. This landslide mass has the potential to rapidly move into Tidal Inlet and generate large, long-period-impulse tsunami waves. Field and photographic examination revealed that the landslide moved between 1892 and 1919 after the retreat of the Little Ice Age glaciers from Tidal Inlet in 1890. Global positioning system measurements over a 2-year period show that the perched mass is presently moving at 3–4 cm annually indicating the landslide remains unstable. Numerical simulations of landslide-generated waves suggest that in the western arm of Glacier Bay, wave amplitudes would be greatest near the mouth of Tidal Inlet and slightly decrease with water depth according to Green’s law. As a function of time, wave amplitude would be greatest within approximately 40 min of the landslide entering water, with significant wave activity continuing for potentially several hours.

Alaska↗

USGS2015

Application of a process-based shallow landslide hazard model over a broad area in Central Italy

Process-based models are widely used for rainfall-induced shallow landslide forecasting. Previous studies have successfully applied the U.S. Geological Survey’s Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability (TRIGRS) model (Baum et al. 2002 ) to compute infiltration-driven changes in the hillslopes’ factor of safety on small scales (i.e., tens of square kilometers). Soil data input for such models are difficult to obtain across larger regions. This work describes a novel methodology for the application of TRIGRS over broad areas with relatively uniform hydrogeological properties. The study area is a 550-km 2 region in Central Italy covered by post-orogenic Quaternary sediments. Due to the lack of field data, we assigned mechanical and hydrological property values through a statistical analysis based on literature review of soils matching the local lithologies. We calibrated the model using rainfall data from 25 historical rainfall events that triggered landslides. We compared the variation of pressure head and factor of safety with the landslide occurrence to identify the best fitting input conditions. Using calibrated inputs and a soil depth model, we ran TRIGRS for the study area. Receiver operating characteristic (ROC) analysis, comparing the model’s output with a shallow landslide inventory, shows that TRIGRS effectively simulated the instability conditions in the post-orogenic complex during historical rainfall scenarios. The implication of this work is that rainfall-induced landslides over large regions may be predicted by a deterministic model, even where data on geotechnical and hydraulic properties as well as temporal changes in topography or subsurface conditions are not available.

Esino river basin, Marche region↗

USGS2019

Characterizing the catastrophic 2017 Mud Creek Landslide, California, using repeat Structure-from-Motion (SfM) photogrammetry

Along the rugged coast of Big Sur, California, the Mud Creek landslide failed catastrophically on May 20, 2017 and destroyed over 400 m of scenic California State Highway 1. We collected structure-from-motion (SfM) photogrammetry data using airborne platforms that, when combined with existing airborne lidar data, revealed that the area exhibited significant topographic change and displacement before, during and after the catastrophic failure. Before the catastrophic failure we document two areas of elevated change in the zone of depletion, which aligned with the double-peaked head scarp produced by the catastrophic failure. The catastrophic failure extended from 337 m elevation to at least 8 m below sea level, was 490 m wide, displaced ~3 million m3 of earth and rock, and deposited landslide debris at least 175 m seaward of the original shoreline. The failure was not a complete slope-clearing event, however, and several upslope and lateral regions that did not slip into the ocean exhibited significant displacement and topographic change during the days and months after catastrophic failure. Additionally, we use the post-slide data to quantify several other processes, including the time-varying rates of talus accumulation and coastal erosion of the landslide toe. We conclude that repeat SfM surveys from aerial imagery can provide valuable information about landslide evolution and the potential for deep-seated landslide hazards – especially in the lead up to catastrophic failure – if photos are collected and processed regularly.

California↗

USGS2014

Source and progression of a submarine landslide and tsunami: The 1964 Great Alaska earthquake at Valdez

Like many subduction zone earthquakes, the deadliest aspects of the 1964 M = 9.2 Alaska earthquake were the tsunamis it caused. The worst of these were generated by local submarine landslides induced by the earthquake. These caused high runups, engulfing several coastal towns in Prince William Sound. In this paper, we study one of these cases in detail, the Port Valdez submarine landslide and tsunami. We combine eyewitness reports, preserved film, and careful posttsunami surveys with new geophysical data to inform numerical models for landslide tsunami generation. We review the series of events as recorded at Valdez old town and then determine the corresponding subsurface events that led to the tsunami. We build digital elevation models of part of the pretsunami and posttsunami fjord‐head delta. Comparing them reveals a ~1500 m long region that receded 150 m to the east, which we interpret as the primary delta landslide source. Multibeam imagery and high‐resolution seismic reflection data identify a ~400 m wide chute with hummocky deposits at its terminus, which may define the primary slide path. Using these elements we run hydrodynamic models of the landslide‐driven tsunamis that match observations of current direction, maximum inundation, and wave height at Valdez old town. We speculate that failure conditions at the delta front may have been influenced by manmade changes in drainage patterns as well as the fast retreat of Valdez and other glaciers during the past century.

Alaska↗

USGS2007

Modeling the spatial distribution of landslide-prone colluvium and shallow groundwater on hillslopes of Seattle, WA

Landslides in partially saturated colluvium on Seattle, WA, hillslopes have resulted in property damage and human casualties. We developed statistical models of colluvium and shallow-groundwater distributions to aid landslide hazard assessments. The models were developed using a geographic information system, digital geologic maps, digital topography, subsurface exploration results, the groundwater flow modeling software VS2DI and regression analyses. Input to the colluvium model includes slope, distance to a hillslope-crest escarpment, and escarpment slope and height. We developed different statistical relations for thickness of colluvium on four landforms. Groundwater model input includes colluvium basal slope and distance from the Fraser aquifer. This distance was used to estimate hydraulic conductivity based on the assumption that addition of finer-grained material from down-section would result in lower conductivity. Colluvial groundwater is perched so we estimated its saturated thickness. We used VS2DI to establish relations between saturated thickness and the hydraulic conductivity and basal slope of the colluvium. We developed different statistical relations for three groundwater flow regimes. All model results were validated using observational data that were excluded from calibration. Eighty percent of colluvium thickness predictions were within 25% of observed values and 88% of saturated thickness predictions were within 20% of observed values. The models are based on conditions common to many areas, so our method can provide accurate results for similar regions; relations in our statistical models require calibration for new regions. Our results suggest that Seattle landslides occur in native deposits and colluvium, ultimately in response to surface-water erosion of hillstope toes. Regional groundwater conditions do not appear to strongly affect the general distribution of Seattle landslides; historical landslides were equally dispersed within and outside of the area potentially affected by regional groundwater conditions.

Earth Surface Processes and Landforms↗

USGS2014

Evaluating a slope-stability model for shallow rain-induced landslides using gage and satellite data

Improving prediction of landslide early warning systems requires accurate estimation of the conditions that trigger slope failures. This study tested a slope-stability model for shallow rainfall-induced landslides by utilizing rainfall information from gauge and satellite records. We used the TRIGRS model (Transient Rainfall Infiltration and Grid-based Regional Slope-stability analysis) for simulating the evolution of the factor of safety due to rainfall infiltration. Using a spatial subset of a well-characterized digital landscape from an earlier study, we considered shallow failure on a slope adjoining an urban transportation roadway near the Seattle area in Washington, USA. We ran the TRIGRS model using high-quality rain gage and satellite-based rainfall data from the Tropical Rainfall Measuring Mission (TRMM). Preliminary results with parameterized soil depth values suggest that the steeper slope values in this spatial domain have factor of safety values that are extremely close to the failure limit within an extremely narrow range of values, providing multiple false alarms. When the soil depths were constrained using a back analysis procedure to ensure that slopes were stable under initial condtions, the model accurately predicted the timing and location of the landslide observation without false alarms over time for gage rain data. The TRMM satellite rainfall data did not show adequately retreived rainfall peak magnitudes and accumulation over the study period, and as a result failed to predict the landslide event. These preliminary results indicate that more accurate and higher-resolution rain data (e.g., the upcoming Global Precipitation Measurement (GPM) mission) are required to provide accurate and reliable landslide predictions in ungaged basins.

Book chapter↗

USGS2010

Distribution and tsunamigenic potential of submarine landslides in the Gulf of Mexico

The Gulf of Mexico (GOM) is a geologically diverse ocean basin that includes three distinct geologic provinces: a carbonate province, a salt province, and canyon to deep-sea fan province, all of which contain evidence of submarine mass movements. The threat of submarine landslides in the GOM as a generator of near-field damaging tsunamis has not been widely addressed. Submarine landslides in the GOM are considered a potential tsunami hazard because: (1) some dated landslides in the GOM have post-glacial ages and (2) recent seismicity recorded within the GOM. We present a brief review of the distribution and style of submarine landslides that have occurred in the GOM during the Quaternary, followed by preliminary hydrodynamic modeling results of tsunami generation from the East Breaks landslide off Corpus Christie, TX.

Book chapter↗

USGS2010

Tree-ring dated landslide movements and seismic events in southwestern Montana, USA

Because many tree species can live for several centuries or longer (Brown 1996), tree-ring analysis can be a valuable tool to date geomorphic events such as landslides, earthquakes, and avalanches in regions lacking long historical records. Typically, a catastrophic landslide will destroy all trees on the landslide, but trees on slower moving landslides may survive. For example, the Slumgullion earthflow, in southwestern Colorado, moves 0.5–5.5 m annually, yet is covered by aspen ( Populus tremuloides ) and conifers (Baum and Fleming 1996). Trees that survive such movements undoubtedly suffer damage, such as topping, tilting, impact, or root breakage. This damage is commonly recorded in the tree-ring record and analysis of this record can be used to reconstruct past landslide activity.

Book chapter↗

USGS1976

Landslides - Cause and effect

Landslides can cause seismic disturbances; landslides can also result from seismic disturbances, and earthquake-induced slides have caused loss of life in many countries. Slides can cause disastrous flooding, particularly when landslide dams across streams are breached, and flooding may trigger slides. Slope movement in general is a major process of the geologic environment that places constraints on engineering development. In order to understand and foresee both the causes and effects of slope movement, studies must be made on a regional scale, at individual sites, and in the laboratory. Areal studies — some embracing entire countries — have shown that certain geologic conditions on slopes facilitate landsliding; these conditions include intensely sheared rocks; poorly consolidated, fine-grained clastic rocks; hard fractured rocks underlain by less resistant rocks; or loose accumulations of fine-grained surface debris. Field investigations as well as mathematical- and physical-model studies are increasing our understanding of the mechanism of slope movement in fractured rock, and assist in arriving at practical solutions to landslide problems related to all kinds of land development for human use. Progressive failure of slopes has been studied in both soil and rock mechanics. New procedures have been developed to evaluate earthquake response of embankments and slopes. The finite element method of analysis is being extensively used in the calculation of slope stability in rock broken by joints, faults, and other discontinuities.

Bulletin of the International Association of Engin↗

USGS2016

Source characterization and tsunami modeling of submarine landslides along the Yucatán Shelf/Campeche Escarpment, southern Gulf of Mexico

Submarine landslides occurring along the margins of the Gulf of Mexico (GOM) represent a low-likelihood, but potentially damaging source of tsunamis. New multibeam bathymetry coverage reveals that mass wasting is pervasive along the Yucatán Shelf edge with several large composite landslides possibly removing as much as 70 km 3 of the Cenozoic sedimentary section in a single event. Using GIS-based analysis, the dimensions of six landslides from the central and northern sections of the Yucatán Shelf/Campeche Escarpment were determined and used as input for preliminary tsunami generation and propagation models. Tsunami modeling is performed to compare the propagation characteristics and distribution of maximum amplitudes throughout the GOM among the different landslide scenarios. Various factors such as landslide geometry, location along the Yucatán Shelf/Campeche Escarpment, and refraction during propagation result in significant variations in the affected part of the Mexican and US Gulf Coasts. In all cases, however, tsunami amplitudes are greatest along the northern Yucatán Peninsula.

Pure and Applied Geophysics↗

USGS1990

Summit Lake landslide and geomorphic history of Summit Lake basin, northwestern Nevada

The Summit Lake landslide, northwestern Nevada, composed of Early Miocene pyroclastic debris, Ashdown Tuff, and basalt and rhyolite of the Black Rock Range, blocked the upper Soldier Creek-Snow Creek drainage and impounded Summit Lake sometimes prior to 7840 yr B.P. The slide covers 8.2 km 2 and has geomorphic features characteristic of long run-out landslides, such as lobate form, longitudinal and transverse ridges, low surface gradient (7.1 °), and preservation of original stratigraphic position of transported blocks. However, estimated debris volume is the smallest reported (2.5 × 10 5 m 3 ) for a landslide of this type. The outflow channel of the Summit Lake basin was a northward-flowing stream valley entrenched by Mahogany Creek. Subsequent negative tectonic adjustment of the basin by about 35 m, accompanied by concommitant progradation of a prominent alluvial fan deposited by Mahogany Creek, argues for a probable diversion of drainage from the Alvord basin southward into the Lahontan basin. The landslide occurred while the creek flowed southward, transferring about 147 km 2 of watershed from the Lahontan basin back to the Alvord basin. Overflow northward occurred during high stands of Pluvial Lake Parman in the basin; otherwise, under drier climates, the Summit Lake basin has been closed. Within large depressions on the slide surface, the ca. 6800 yr old Mazama Bed and other sediments have buried a weakly developed soil. Disseminated humus in the soil yields an age of 7840 ± 310 yr B.P. Absence of older tephra (such as St. Helens M) brackets the slide age between 7840 and 19,000 yr B.P. Projectile points found on the highest strandlines of Pluvial Lake Parman suggest a ca 8700 yr B.P. age by correlation with cultural artifacts and radiocarbon ages from nearby Last Supper Cave, Nevada. Organic matter accumulation in landslide soils suggests ages ranging from 9100 to 16,250 yr B.P. Estimation of the age of the slide from morphologic data for the isolated Summit Lake population of Lahontan cutthroat trout does not conflict with the radiometric ages.

Geomorphology↗

USGS1995

Can magma-injection and groundwater forces cause massive landslides on Hawaiian volcanoes?

Landslides with volumes exceeding 1000 km 3 have occurred on the flanks of Hawaiian volcanoes. Because the flanks typically slope seaward no more than 12 °, the mechanics of slope failure are problematic. Limit-equilibrium analyses of wedge-shaped slices of the volcano flanks show that magma injection at prospective headscarps might trigger the landslides, but only under very restrictive conditions. If static magma weight is the sole source of magma pressure, hypothetical flank failures can have any size, but can occur only if slip-surface friction angles are less than about 16 °. If slip surfaces have friction angles more typical of fragmented or intact rocks (30–40 °), flank failures can occur only if mean magma pressures exceed static equilibrium pressures. Landslide length then scales with the excess magma pressure divided by the buoyant unit weight of the volcano flank. For typical excess magma pressures, buoyant unit weights and rock friction angles, the largest landslides that might be triggered in this manner have lengths of only several kilometers. This is at least an order of magnitude too small to explain the occurrence of giant Hawaiian landslides. The growing mass of active Hawaiian volcanoes can compress the edifice and substrate rocks and consequently produce groundwater head gradients that might destabilize larger sectors of the volcano flanks. However, calculations show that volcano growth at an estimated long-term vertical rate of 0.02 m/yr can generate significant head gradients only if an areally extensive, buried clay layer exists that has a great thickness (~ 200 m) or very low hydraulic diffusivity (~ 10 −11 m 2 /s). Additional calculations show that groundwater head gradients associated with topographically induced flow and sea-level change are less likely to be important. Thus a simple, quantitative explanation for failure of Hawaiian volcano flanks remains elusive, and more complex scenarios may merit investigation.

Journal of Volcanology and Geothermal Research↗

USGS2019

Catastrophic landscape modification from a massive landslide tsunami in Taan Fiord, Alaska

The October 17th, 2015 Taan Fiord landslide and tsunami generated a runup of 193 m, nearly an order of magnitude greater than most previously surveyed tsunamis. To date, most post-tsunami surveys are from earthquake-generated tsunamis and the geomorphic signatures of landslide tsunamis or their potential for preservation are largely uncharacterized. Additionally, clear modifications described during previous post-tsunami surveys are often ephemeral and unlikely to be preserved. Documented geomorphic modifications of several low gradient fan deltas within Taan Fiord make it an excellent laboratory for characterizing signatures of a landslide tsunami event. Geomorphic changes to fan deltas in Taan Fiord caused by the landslide-generated tsunami included complete vegetation loss over more than 0.6 km2 of fan surfaces, formation of steep fan front scarps up to 10 m high, extensive local alterations of fan topography, and formation of new tsunami return-flow channels. Two relatively stable fan deltas in Taan Fiord were heavily vegetated prior to the Taan event and may preserve features of tsunami modification for decades to centuries. If this is the case, fan deltas may be a previously unrecognized location for preservation of tsunami signatures in the recent past. Fans in poorly monitored regions, such as Greenland, could thus hold evidence of previously unidentified recent landslide tsunami events.

Alaska↗

USGS2017

Tree-ring dated landslide movements and their relationship to seismic events in southwestern Montana, USA

To determine periods of incremental landslide movement and their possible relationship to regional seismic events, the tree-ring records of 32 titled and damaged conifers at three sites on landslides in the Gravelly Range of southwestern Montana were examined. Several signs of disturbance in the tree-ring record indicating landslide movement were observed. Commonly, the tree-ring record displayed a marked reduction in annual ring width and/or the reaction wood formation. The tree-ring records from the three landslide sites indicate multiple periods of movement during the 20th century. Many of the periods of movement indicated by the strongest signals (most trees) at the sites occurred the year following significant earthquakes in the region. Those seismic events for which evidence in the tree-ring record was found at one or more of the three sites are the 1983 Borah Peak, 1959 Hebgen Lake, 1935 Helena, 1925 Clarkson, and 1908 Virginia City earthquakes. This study suggests that many of the landslide movements were triggered by, or are coincident with, earthquakes as much as 200 km from the study area.

Montana↗

USGS2002

The proximal part of the giant submarine Wailau landslide, Molokai, Hawaii

The main break-in-slope on the northern submarine flank of Molokai at -1500 to -1250 m is a shoreline feature that has been only modestly modified by the Wailau landslide. Submarine canyons above the break-in-slope, including one meandering stream, were subaerially carved. Where such canyons cross the break-in-slope, plunge pools may form by erosion from bedload sediment carried down the canyons. West Molokai Volcano continued infrequent volcanic activity that formed a series of small coastal sea cliffs, now submerged, as the island subsided. Lavas exposed at the break-in-slope are subaerially erupted and emplaced tholeiitic shield lavas. Submarine rejuvenated-stage volcanic cones formed after the landslide took place and following at least 400-500 m of subsidence after the main break-in-slope had formed. The sea cliff on east Molokai is not the headwall of the landslide, nor did it form entirely by erosion. It may mark the location of a listric fault similar to the Hilina faults on present-day Kilauea Volcano. The Wailau landslide occurred about 1.5 Ma and the Kalaupapa Peninsula most likely formed 330??5 ka. Molokai is presently stable relative to sea level and has subsided no more than 30 m in the last 330 ka. At their peak, West and East Molokai stood 1.6 and 3 km above sea level. High rainfall causes high surface runoff and formation of canyons, and increases groundwater pressure that during dike intrusions may lead to flank failure. Active shield or postshield volcanism (with dikes injected along rift zones) and high rainfall appear to be two components needed to trigger the deep-seated giant Hawaiian landslides. ?? 2002 Elsevier Science B.V. All rights reserved.

Journal of Volcanology and Geothermal Research↗

USGS2010

Estimating the timing and location of shallow rainfall-induced landslides using a model for transient, unsaturated infiltration

Shallow rainfall-induced landslides commonly occur under conditions of transient infiltration into initially unsaturated soils. In an effort to predict the timing and location of such landslides, we developed a model of the infiltration process using a two-layer system that consists of an unsaturated zone above a saturated zone and implemented this model in a geographic information system (GIS) framework. The model links analytical solutions for transient, unsaturated, vertical infiltration above the water table to pressure-diffusion solutions for pressure changes below the water table. The solutions are coupled through a transient water table that rises as water accumulates at the base of the unsaturated zone. This scheme, though limited to simplified soil-water characteristics and moist initial conditions, greatly improves computational efficiency over numerical models in spatially distributed modeling applications. Pore pressures computed by these coupled models are subsequently used in one-dimensional slope-stability computations to estimate the timing and locations of slope failures. Applied over a digital landscape near Seattle, Washington, for an hourly rainfall history known to trigger shallow landslides, the model computes a factor of safety for each grid cell at any time during a rainstorm. The unsaturated layer attenuates and delays the rainfall-induced pore-pressure response of the model at depth, consistent with observations at an instrumented hillside near Edmonds, Washington. This attenuation results in realistic estimates of timing for the onset of slope instability (7 h earlier than observed landslides, on average). By considering the spatial distribution of physical properties, the model predicts the primary source areas of landslides.

Journal of Geophysical Research F: Earth Surface↗