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, Engineering Geology
Science and Products
Landslide Mechanisms and Forecasting
Puerto Rico Landslide Monitoring Network
Puerto Rico Natural Hazards: Landslides | Peligros naturales de Puerto Rico: Deslizamientos de tierra
Rainfall-Induced Landslides in Puerto Rico
Slow-Motion Landslides
Field observations of landslides and related materials following Hurricane Maria, Puerto Rico
Map data from landslides triggered by Hurricane Maria in select areas of San Lorenzo, Puerto Rico
Map data from landslides triggered by Hurricane Maria in two study areas in the Las Marías Municipality, Puerto Rico
Model input and output data covering Lares Municipio, Utuado Municipio, and Naranjito Municipio, Puerto Rico, for landslide initiation susceptibility assessment after Hurricane Maria
Modified basal contact of the Tertiary Lares Limestone in the vicinity of Utuado, Puerto Rico, USA, derived from USGS Open-File Report 98-038
Map data from landslides triggered by Hurricane Maria in the greater karst region of northwest Puerto Rico
Map data from landslides triggered by Hurricane Maria in four study areas in the Utuado Municipality, Puerto Rico
Geographic Information System Layer of a Map Depicting Susceptibility to Landslides Triggered by Intense Rainfall, Puerto Rico
Slow-moving landslides near the U.S. West Coast mapped from ALOS and ALOS-2 InSAR, 2007-2019
Map data from landslides triggered by Hurricane Maria in a section of Naranjito, Puerto Rico
Map data from landslides triggered by Hurricane Maria in three study areas in the Lares Municipality, Puerto Rico
Precipitation and soil-moisture data from the Two Towers landslide, Trinity County, California
Landslides triggered by the 2002 M 7.9 Denali Fault earthquake, Alaska, USA
Geologic controls of slow-moving landslides near the U.S. West Coast
When hazard avoidance is not an option: Lessons learned from monitoring the postdisaster Oso landslide, USA
High-resolution soil-moisture maps over landslide regions in northern California grassland derived From SAR backscattering coefficients
Landslide guide for residents of Puerto Rico
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
Mobility characteristics of landslides triggered by Hurricane Maria in Puerto Rico
Four-dimensional surface motions of the Slumgullion landslide and quantification of hydrometeorological forcing
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
Using a dense seismic array to determine structure and site effects of the Two Towers earthflow in northern California
Widespread initiation, reactivation, and acceleration of landslides in the northern California Coast Ranges due to extreme rainfall
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
Science and Products
- Science
Landslide Mechanisms and Forecasting
When and where will landslides happen? How far will they go, how big and how fast will they be? These questions are difficult to answer because many factors contribute to landslide occurrence, magnitude, and mobility; some factors remain unknown, while nearly all are very difficult to quantify and account for. Researchers use surface, subsurface, remote sensing, and laboratory observations along...Puerto Rico Landslide Monitoring Network
The USGS and the University of Puerto Rico-Mayagüez installed instruments to monitor hillslope hydrological conditions in fifteen municipalities in mountainous regions across Puerto Rico.Puerto Rico Natural Hazards: Landslides | Peligros naturales de Puerto Rico: Deslizamientos de tierra
The Landslide Hazards Program from USGS works to help reduce the impact of landslides to people and infrastructure by furthering our understanding of causes of ground failure and by recommending strategies for risk mitigation. In Puerto Rico, USGS researchers have rigorously studied rainfall-induced landslides to provide maps that depict landslide susceptibility. Educational materials that...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.Slow-Motion Landslides
Release Date: JUNE 11, 2018 Sluggishly-moving earthflows can help us learn what controls the starting and stopping of landslides. - Data
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Field observations of landslides and related materials following Hurricane Maria, Puerto Rico
During September 2017, Hurricane Maria caused widespread landsliding throughout mountainous regions of Puerto Rico, with more than 71,000 landslides being subsequently identified from aerial imagery (Hughes et al., 2019). Most landslides apparently mobilized as debris flows and occurred within soil (unconsolidated material overlying saprolite and bedrock) and saprolite overlying less-weathered rocMap data from landslides triggered by Hurricane Maria in select areas of San Lorenzo, Puerto Rico
Hurricane Maria brought intense rainfall and 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 two areas in San Lorenzo, which is a municipality in the east-central part of the main island. To study a characteristMap data from landslides triggered by Hurricane Maria in two study areas in the Las Marías Municipality, Puerto Rico
In late September 2017, intense precipitation associated with Hurricane Maria caused extensive landsliding across Puerto Rico. Much of the Las Marías 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 ofModel input and output data covering Lares Municipio, Utuado Municipio, and Naranjito Municipio, Puerto Rico, for landslide initiation susceptibility assessment after Hurricane Maria
Hurricane Maria induced about 70,000 landslides throughout Puerto Rico, USA (Hughes and others, 2019). Data in this project pertain to two areas situated in Puerto Rico’s rugged Cordillera Central range. Combined, these areas account for more than half of the hurricane-induced landslides. One of these areas encloses two neighboring municipalities, Lares Municipio, and Utuado Municipio, and the secModified basal contact of the Tertiary Lares Limestone in the vicinity of Utuado, Puerto Rico, USA, derived from USGS Open-File Report 98-038
This dataset comprises a vector shapefile of the Puerto Rico geologic map from Bawiec et al. (1999), clipped to study areas in the Lares, Utuado, and Naranjito municipalities, with a modified basal contact of the Tertiary Lares Limestone (Tla) re-mapped using a lidar-derived digital elevation model (DEM) (USGS, 2018). The limestone unit of interest forms a prominent break in slope with the underlyMap 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 northweMap data from landslides triggered by Hurricane Maria in four study areas in the Utuado Municipality, Puerto Rico
In late September 2017, intense precipitation associated with Hurricane Maria caused extensive landsliding across Puerto Rico. Much of the Utuado municipality in central 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 landslide ocGeographic 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.orSlow-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 SynthetiMap 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 landslidMap 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 landsPrecipitation and soil-moisture data from the Two Towers landslide, Trinity County, California
We performed hourly monitoring of precipitation and soil moisture at the Two Towers landslide located in northern California near the town of Zenia. Data were acquired January 19, 2017 to April 29, 2020. Rainfall was measured near the center of the landslide using a tipping-bucket rain gauge with resolution of 0.254 mm and accuracy of ±2% to 250 mm/h (resolutions and accuracies stated herein are a - Publications
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Landslides triggered by the 2002 M 7.9 Denali Fault earthquake, Alaska, USA
The 2002 M 7.9 Denali earthquake in Alaska, USA, was the largest inland earthquake in North America in nearly 150 years. The earthquake involved oblique thrusting but mostly strike-slip motion, and faults ruptured the ground surface over 330 km. Fault rupture occurred in a rugged, mountainous, subarctic environment with extensive permafrost and variable glaciation, geology, and groundwater presencAuthorsWilliam SchulzGeologic 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 m2AuthorsYuankun Xu, William Schulz, Zhong Lu, Jinwook Kim, Kelli Wadsworth BaxstromWhen 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 collapsAuthorsMark E. Reid, Jonathan W. Godt, Richard G LaHusen, Stephen L Slaughter, Thomas C. Badger, Brian D. Collins, William Schulz, Rex L. Baum, Jeffrey A. Coe, Edwin L Harp, Kevin M. Schmidt, Richard M. Iverson, Joel B. Smith, Ralph Haugerud, David L. GeorgeHigh-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, usingAuthorsTien-Hao Liao, Seung-bum Kim, Alexander L. Handwerger, Eric J. Fielding, Michael H. Cosh, William SchulzLandslide guide for residents of Puerto Rico
No abstract available.AuthorsLindsay Ann Davis, Jocelyn West, Lori Peek, K. Stephen Hughes, James Joyce, William Schulz, Jonathan W. Godt, Darysabel Perez Martinez, Gisela Baez Sanchez, Glorymar Gomez Perez, Carolina Hincapie Cardenas, Christa von Hillebrandt, Lorna Jaramillo-Nieves, Jenniffer Santos-Hernandez, Raquel Lugo Bendezú, Yahaira Álvarez GandíaTwelve-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 measureAuthorsY. Xu, Z. Lu, William Schulz, J. KimMobility 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 differeAuthorsErin K. Bessette-Kirton, Jeffrey A. Coe, William Schulz, Corina Cerovski-Darriau, Mason Muir EinbundFour-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 hyAuthorsXie Hu, Roland Bürgmann, William Schulz, Eric J. FieldingMap 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
AuthorsK. Stephen Hughes, William SchulzUsing 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 vAuthorsAmanda M. Thomas, Zack Spica, Miles Bodmer, William Schulz, Joshua J. RoeringWidespread 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 ocAuthorsAlexander L. Handwerger, Eric J. Fielding, Mong-Han Huang, Georgina L. Bennett, Cunren Liang, William SchulzLandslides 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
AuthorsErin Bessette-Kirton, Corina Cerovski-Darriau, William Schulz, Jeffrey A. Coe, Jason W. Kean, Jonathan W. Godt, Matthew A. Thomas, K. Stephen Hughes