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William Schulz

I have worked as a research geologist in the Landslide Hazards Program of the U.S. Geological Survey since 2002.

Prior to that, I worked in the private sector in California and Wisconsin, mostly investigating landslides and seismogenic ground displacement. My research primarily focuses on understanding conditions that result in the diverse characteristics of landslide motion, although I am also very interested in understanding controls of the onset of landslide movement and reactivation. My work includes characterizing and monitoring landslides in the field, laboratory testing, mathematical modeling, and assessing landslide hazards.

 

Education and Certifications

  • University of Wisconsin, Milwaukee, B.S., 1994, Geology

    Purdue University, M.S., 1996, Engineering Geology

    Kyoto University, Ph.D., 2020, Geophysics

Science and Products

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house on slope that is slipping down and falling apart

Rainfall-Induced Landslides in Puerto Rico

In September 2017 Hurricane María triggered more than 70,000 landslides across Puerto Rico that caused loss of life and widespread damage to transportation, communication, and power-supply infrastructure, and to other public and private property.
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Natural Hazards, Landslide Hazards
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Rainfall-Induced Landslides in Puerto Rico

In September 2017 Hurricane María triggered more than 70,000 landslides across Puerto Rico that caused loss of life and widespread damage to transportation, communication, and power-supply infrastructure, and to other public and private property.
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The Two Towers landslide, looking upslope from the bottom.

Slow-Motion Landslides

Release Date: JUNE 11, 2018Sluggishly-moving earthflows can help us learn what controls the starting and stopping of landslides.
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Natural Hazards, Landslide Hazards
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Slow-Motion Landslides

Release Date: JUNE 11, 2018Sluggishly-moving earthflows can help us learn what controls the starting and stopping of landslides.
Learn More

Geographic Information System Layer of a Map Depicting Susceptibility to Landslides Triggered by Intense Rainfall, Puerto Rico

This data release comprises a georeferenced raster layer depicting the estimated susceptibility to intense rainfall-induced landslides in Puerto Rico, which is a supplement to: Hughes, K.S., and Schulz, W.H., 2020, Map depicting susceptibility to landslides triggered by intense rainfall, Puerto Rico: U.S. Geological Survey Open-File Report 2020-1022, 91 p., 1 plate, scale 1:150,000, https://doi.or
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Landslide Hazards

Slow-moving landslides near the U.S. West Coast mapped from ALOS and ALOS-2 InSAR, 2007-2019

This data set provides a polygon shapefile delineating relatively large, slow-moving (4-17 cm/year in the radar line-of-sight direction) landslides in the continental U.S. western coastal states (California, Oregon, and Washington). The polygons also are provided in a Google Earth .kmz file. Delineated landslides were identified from displacement signals captured by InSAR (Interferometric Syntheti
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Geologic Hazards Science Center

Map data from landslides triggered by Hurricane Maria in a section of Naranjito, Puerto Rico

Hurricane Maria caused widespread landsliding throughout Puerto Rico during September 2017. Previous detailed landslide inventories following the hurricane include Bessette-Kirton et al. (2017, 2019). Here we continue that work with an in-depth look at a portion of northwest Naranjito, which is a municipality in the northeastern part of the main island. To study a characteristic sample of landslid
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Geologic Hazards Science Center

Map data from landslides triggered by Hurricane Maria in three study areas in the Lares Municipality, Puerto Rico

In late September 2017, intense precipitation associated with Hurricane Maria caused extensive landsliding across Puerto Rico. Much of the Lares municipality in central-western Puerto Rico was severely impacted by landslides. Landslide density in this region was mapped as greater than 25 landslides/km2 (Bessette-Kirton et al., 2019). In order to better understand the controlling variables of lands
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Geologic Hazards Science Center

Map data from landslides triggered by Hurricane Maria in the greater karst region of northwest Puerto Rico

Hurricane Maria caused widespread landsliding throughout Puerto Rico in September 2017. While the majority of landslide inventories following the hurricane focused on mountainous regions underlain by igneous and volcaniclastic bedrock (Bessette-Kirton et al., 2017, 2019), here we fill an important knowledge gap and document the occurrence of landslides along the greater karst region on the northwe
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Geologic Hazards Science Center

Data from in-situ displacement monitoring, Slumgullion landslide, Hinsdale County, Colorado

We monitored displacement of the Slumgullion landslide located in Hinsdale County, Colorado. We measured displacement at the ground surface between 12 August 2011 and 10 October 2018, and in the subsurface between 4 September 2016 and 7 December 2016. Both types of data were acquired at irregular time intervals. Displacement at the ground surface was measured at locations within the upper, middle,
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Landslide Hazards

Map data from landslides triggered by Hurricane Maria in four study areas of Puerto Rico

In September 2017, Hurricane Maria caused widespread landsliding throughout mountainous regions of Puerto Rico. Nearly all landslides mobilized as debris flows (Bessette-Kirton et al., 2019), but herein, we simply use the term "landslides" when describing all types of slope failures that occurred during Hurricane Maria. To examine the extent and physical characteristics of landslides in severely i
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Landslide Hazards

Data from in-situ landslide monitoring, Trinity County, California

We performed hourly monitoring of conditions at the Two Towers landslide located in northern California near the town of Zenia. Monitored conditions included rainfall, groundwater head, horizontal total stress, horizontal effective stress, vertical soil deformation, and subsurface displacement. Data were acquired November 11, 2014-July 22, 2017, except for times during which power failure occurred
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Landslide Hazards

Data related to a ground-based InSAR survey of the Slumgullion landslide, Hinsdale County, Colorado, 26 June 2010-1 July 2010

We performed a ground-based, interferometric, synthetic aperture radar (InSAR) survey of the Slumgullion landslide located in Hinsdale County, Colorado. The survey was performed 26 June 2010-1 July 2010 and utilized the IBIS-L InSAR system developed by IDS Corporation. Radar measurements were supplemented by hourly in-situ displacement, pore-water pressure, and rainfall measurements. In-situ displ
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Landslide Hazards
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Geologic controls of slow-moving landslides near the U.S. West Coast

Slow-moving landslides, often with nearly imperceptible creeping motion, are an important landscape shaper and a dangerous natural hazard across the globe, yet their spatial distribution and geologic controls are still poorly known owing to a paucity of detailed, large-area observations. Here, we use interferometry of L-band satellite radar images to reveal 617 spatially large (4 × 104–13 × 106 m2
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

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

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 collaps
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Landslide Hazards, Volcano Hazards, Volcano Science Center, Geologic Hazards Science Center

High-resolution soil-moisture maps over landslide regions in northern California grassland derived From SAR backscattering coefficients

Slow-moving landslides are destabilized by accumulated precipitation and consequent soil moisture. Yet, the continuous high-resolution soil-moisture measurements needed to aid the understanding of landslide processes are generally absent in steep terrain. Here, we produce soil-moisture time-series maps for a seasonally active grassland landslide in the northern California coast ranges, USA, using
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Natural Hazards, Geologic Hazards Science Center

Twelve-year dynamics and rainfall thresholds for alternating creep and rapid movement of the Hooskanaden landslide from integrating InSAR, pixel offset tracking, and borehole and hydrological measurements

The Hooskanaden landslide is a large (~600 m wide × 1,300 m long), deep (~30 – 45 m) slide located in southwestern Oregon. Since 1958, it has had five moderate/major movements that catastrophically damaged the intersecting U.S. Highway 101, along with persistent slow wet‐season movements and a long‐term accelerating trend due to coastal erosion. Multiple remote sensing approaches, borehole measure
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

Mobility characteristics of landslides triggered by Hurricane Maria in Puerto Rico

Mobility is an important element of landslide hazard and risk assessments yet has been seldom studied for shallow landslides and debris flows in tropical environments. In September 2017, Hurricane Maria triggered > 70,000 landslides across Puerto Rico. Using aerial imagery and a lidar digital elevation model (DEM), we mapped and characterized the mobility of debris slides and flows in four differe
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

Four-dimensional surface motions of the Slumgullion landslide and quantification of hydrometeorological forcing

Landslides modify the natural landscape and cause fatalities and property damage worldwide. Quantifying landslide dynamics is challenging due to the stochastic nature of the environment. With its large area of ~1 km2 and perennial motions at ~10–20 mm per day, the Slumgullion landslide in Colorado, USA, represents an ideal natural laboratory to better understand landslide behavior. Here, we use hy
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Natural Hazards, Geologic Hazards Science Center

Map depicting susceptibility to landslides triggered by intense rainfall, Puerto Rico

Landslides in Puerto Rico range from nuisances to deadly events. Centuries of agricultural and urban modification of the landscape have perturbed many already unstable hillsides on the tropical island. One of the main triggers of mass wasting on the island is the high-intensity rainfall that is associated with tropical atmospheric systems. Puerto Rico’s geographic position and rugged topography re
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

Using a dense seismic array to determine structure and site effects of the Two Towers earthflow in northern California

We deployed a network of 68 three-component geophones on the slow moving Two Towers earthflow in northern California. We compute horizontal-to-vertical spectral ratios (HVSRs) from the ambient seismic field. The HVSRs have two prominent peaks, one near 1.23 Hz and another between 4 and 8 Hz at most stations. The 1.23 Hz resonance is a property of the background noise field and may be due to a v
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Natural Hazards, Landslide Hazards, Central Energy Resources Science Center, Geologic Hazards Science Center

Widespread initiation, reactivation, and acceleration of landslides in the northern California Coast Ranges due to extreme rainfall

Episodically to continuously active slow-moving landslides are driven by precipitation. Climate change, which is altering both the frequency and magnitude of precipitation world21 wide, is therefore predicted to have a major impact on landslides. Here we examine the behavior of hundreds of slow-moving landslides in northern California in response to large changes in annual precipitation that oc
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

Landslides triggered by Hurricane Maria: Assessment of an extreme event in Puerto Rico

Hurricane Maria hit the island of Puerto Rico on 20 September 2017 and triggered more than 40,000 landslides in at least three-fourths of Puerto Rico’s 78 municipalities. The number of landslides that occurred during this event was two orders of magnitude greater than those reported from previous hurricanes. Landslide source areas were commonly limited to surficial soils but also extended into und
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

Clayey landslide initiation and acceleration strongly modulated by soil swelling

Largely unknown mechanisms restrain motion of clay-rich, slow-moving landslides that are widespread worldwide and rarely accelerate catastrophically. We studied a clayey, slow-moving landslide typical of thousands in northern California, USA, to decipher hydrologic-mechanical interactions that modulate landslide dynamics. Similar to some other studies, observed pore-water pressures correlated poor
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

Landslide kinematics and their potential controls from hourly to decadal timescales: Insights from integrating ground-based InSAR measurements with structural maps and long-term monitoring data

Knowledge of kinematics is rudimentary for understanding landslide controls and is increasingly valuable with greater spatiotemporal coverage. However, characterizing landslide-wide kinematics is rare, especially at broadly ranging timescales. We used highly detailed kinematic data obtained using photogrammetry and field mapping during the 1980s and 1990s and our 4.3-day ground-based InSAR survey
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

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