This inventory was originally created by Harp and others (1984) describing the landslides triggered by a sequence of earthquakes, with the largest being the M 6.5 Mammoth Lakes, California earthquake that occurred on 25 May 1980 at 19:44:50 UTC. Care should be taken when comparing with other inventories because different authors use different mapping techniques. This inventory includes landslides triggered by a sequence of earthquakes rather than a single mainshock. Please check the author methods summary and the original data source for more information on these details and to confirm the viability of this inventory for your specific use. With the exception of the data from USGS sources, the inventory data and associated metadata were not acquired by the U.S. Geological Survey (USGS) and thus have not been reviewed for accuracy and completeness by the USGS. They are presented as part of this data series for convenience of the user only, as part of an effort to make published ground-failure inventories more accessible from a single aggregated site. No warranty, expressed or implied, is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

This inventory was originally created by Harp and others (1984) describing the landslides triggered by a sequence of earthquakes, with the largest being the M 6.5 Mammoth Lakes, California earthquake that occurred on 25 May 1980 at 19:44:50 UTC. Care should be taken when comparing with other inventories because different authors use different mapping techniques. This inventory includes landslides triggered by a sequence of earthquakes rather than a single mainshock. Please check the author methods summary and the original data source for more information on these details and to confirm the viability of this inventory for your specific use. With the exception of the data from USGS sources, the inventory data and associated metadata were not acquired by the U.S. Geological Survey (USGS) and thus have not been reviewed for accuracy and completeness by the USGS. They are presented as part of this data series for convenience of the user only, as part of an effort to make published ground-failure inventories more accessible from a single aggregated site. No warranty, expressed or implied, is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

This data release includes time-series data and qualitative descriptions from a monitoring station on a steep, landslide-prone slope above the City of Sitka, Alaska. On August 18, 2015, heavy rainfall triggered around 60 landslides in and around Sitka. These landslides moved downslope rapidly; several were damaging, and one demolished a home on South Kramer Avenue and killed three people. On September 16-18, 2019, the U.S. Geological Survey installed instrumentation at a site near the initiation zones of these landslides and other previous landslides on the west face of Harbor Mountain. The station consists of an electronics enclosure, a mounted rain gage, and two instrumented soil pits. Instruments record continuous measurements of precipitation, air temperature, volumetric water content, pore-water pressure, soil temperature, and soil matric potential at five-minute intervals. Soil pits were dug as deep as possible into the soil mantle for installation of the hydrologic monitoring instruments. Extensive probing with a 1.2-m-long piece of rebar to the point of refusal confirmed that the bottom of each hole was near the top of bedrock or compact till. The first soil pit (SP1), located at N 57.08551, W 135.35936, is about 1 m downslope from the north rim of the drainage hollow. SP1 is about 60 cm deep with the upper 12-15 cm in dark brown, moist, silty sand with large concentration of plant roots. Below 15 cm, to bottom of hole, consists of abundant gray sandstone clasts in silty sand matrix, which ranges in color from orange-brown, brown, to gray. The SP1 sensor array consists of a water potential sensor and soil moisture sensor at 25 cm depth, a second soil moisture sensor at 50 cm depth, and a pressure transducer near bottom of hole with a port at ~55 cm depth. The second soil pit (SP2), located at N 57.08548, W 135.35933, is about 5 m downslope from the north rim of the drainage hollow and is 65 cm deep. The top of hard material (bedrock or till) was about 70 cm deep, but there was free water at a depth of about 50-55 cm. Material throughout the depth of the hole was moist sandy silty clay of a gelatinous consistency. Color ranged from orange-brown to dark brown. Very few stones were present. These soils were interpreted as transported/mixed, weathered volcanic ash (Jacqueline Foss, USDA Forest Service, personal communication, 2019). The SP2 sensor array consists of soil moisture sensors at 25 and 40 cm depth, and a pressure transducer lying on the bottom of the hole, with a port at about 60 cm depth. A Campbell Scientific CR1000 datalogger is used to collect continuous data from these sensors. The datalogger and modem are contained in a sealed, weather-resistant fiberglass enclosure. The CR1000 datalogger contains an internal thermistor that continuously measures temperature. Additionally, an air temperature sensor was installed to collect continuous air temperature data. A tipping bucket rain gage installed in a clearing about 10 m northwest of the logger enclosure collects precipitation data. The maximum resolution of the rain gauge is 0.2 mm; that is, one tip of the bucket represents 0.2 mm. Four METER ECH20 EC-5 sensors are used to collect soil moisture data. Pore-water pressures are measured using two Campbell Scientific CS-451 pressure transducers. A METER MPS-6 water potential sensor in SP1 is used to collect soil matric potential. This sensor’s measurements range from -100,000 to -9 kPa was exceeded for the duration of the monitoring period. Recorded values appear to hover around the sensor’s upper limit (-9 kPa), with the exception of September 2019 when the station was first installed and a few brief periods in July 2022 when conditions were sufficiently dry for matric potentials to drop below -9 kPa. The water potential sensor and pressure sensors have integrated thermistors and the associated temperature readings are included. Several factors that may influence data consistency and/or quality should be

This data release includes time-series data and qualitative descriptions from a monitoring station on a steep, landslide-prone slope above the City of Sitka, Alaska. On August 18, 2015, heavy rainfall triggered around 60 landslides in and around Sitka. These landslides moved downslope rapidly; several were damaging, and one demolished a home on South Kramer Avenue and killed three people. On September 16-18, 2019, the U.S. Geological Survey installed instrumentation at a site near the initiation zones of these landslides and other previous landslides on the west face of Harbor Mountain. The station consists of an electronics enclosure, a mounted rain gage, and two instrumented soil pits. Instruments record continuous measurements of precipitation, air temperature, volumetric water content, pore-water pressure, soil temperature, and soil matric potential at five-minute intervals. Soil pits were dug as deep as possible into the soil mantle for installation of the hydrologic monitoring instruments. Extensive probing with a 1.2-m-long piece of rebar to the point of refusal confirmed that the bottom of each hole was near the top of bedrock or compact till. The first soil pit (SP1), located at N 57.08551, W 135.35936, is about 1 m downslope from the north rim of the drainage hollow. SP1 is about 60 cm deep with the upper 12-15 cm in dark brown, moist, silty sand with large concentration of plant roots. Below 15 cm, to bottom of hole, consists of abundant gray sandstone clasts in silty sand matrix, which ranges in color from orange-brown, brown, to gray. The SP1 sensor array consists of a water potential sensor and soil moisture sensor at 25 cm depth, a second soil moisture sensor at 50 cm depth, and a pressure transducer near bottom of hole with a port at ~55 cm depth. The second soil pit (SP2), located at N 57.08548, W 135.35933, is about 5 m downslope from the north rim of the drainage hollow and is 65 cm deep. The top of hard material (bedrock or till) was about 70 cm deep, but there was free water at a depth of about 50-55 cm. Material throughout the depth of the hole was moist sandy silty clay of a gelatinous consistency. Color ranged from orange-brown to dark brown. Very few stones were present. These soils were interpreted as transported/mixed, weathered volcanic ash (Jacqueline Foss, USDA Forest Service, personal communication, 2019). The SP2 sensor array consists of soil moisture sensors at 25 and 40 cm depth, and a pressure transducer lying on the bottom of the hole, with a port at about 60 cm depth. A Campbell Scientific CR1000 datalogger is used to collect continuous data from these sensors. The datalogger and modem are contained in a sealed, weather-resistant fiberglass enclosure. The CR1000 datalogger contains an internal thermistor that continuously measures temperature. Additionally, an air temperature sensor was installed to collect continuous air temperature data. A tipping bucket rain gage installed in a clearing about 10 m northwest of the logger enclosure collects precipitation data. The maximum resolution of the rain gauge is 0.2 mm; that is, one tip of the bucket represents 0.2 mm. Four METER ECH20 EC-5 sensors are used to collect soil moisture data. Pore-water pressures are measured using two Campbell Scientific CS-451 pressure transducers. A METER MPS-6 water potential sensor in SP1 is used to collect soil matric potential. This sensor’s measurements range from -100,000 to -9 kPa was exceeded for the duration of the monitoring period. Recorded values appear to hover around the sensor’s upper limit (-9 kPa), with the exception of September 2019 when the station was first installed and a few brief periods in July 2022 when conditions were sufficiently dry for matric potentials to drop below -9 kPa. The water potential sensor and pressure sensors have integrated thermistors and the associated temperature readings are included. Several factors that may influence data consistency and/or quality should be

The data presented in this data release represent the records from a rain gage near Black Hollow, CO, a watershed that is tributary to the Cache La Poudre River. On 20 July 2021 a large rainstorm moved over the watershed and generated a large debris flow that destroyed several homes, resulting in four fatalities. The watershed had been burned prior to the rainstorm during the Cameron Peak wildfire (13 August – 2 December 2020). Here we present time-series data the Dry Creek rain gage, which captures the storm that triggered the Black Hollow debris flow. Latitude and Longitude data are included in the header. The Dry Creek rain gage reports the number of tips at timesteps of 5 minutes, and each tip is equal to 0.01 inches of rainfall.

The data presented in this data release represent the records from a rain gage near Black Hollow, CO, a watershed that is tributary to the Cache La Poudre River. On 20 July 2021 a large rainstorm moved over the watershed and generated a large debris flow that destroyed several homes, resulting in four fatalities. The watershed had been burned prior to the rainstorm during the Cameron Peak wildfire (13 August – 2 December 2020). Here we present time-series data the Dry Creek rain gage, which captures the storm that triggered the Black Hollow debris flow. Latitude and Longitude data are included in the header. The Dry Creek rain gage reports the number of tips at timesteps of 5 minutes, and each tip is equal to 0.01 inches of rainfall.

This dataset contains 17 fluvial and hillslope planforms for a 2.25km section of the Nooksack River and adjacent Clay Banks Landslide Complex in northwestern Washington State spanning 1933-2022. Data include polygon and line features of river and hillslope planform structures for each year including landslides, the active river channel, the floodplain corridor, and vegetated floodplain bars. Data is digitized manually in GIS software at a scale of 1:1000 from aerial imagery, including imagery from the Puget Sound River History Project compiled for 1933, 1950, 1955, 1966, 1976, 1986, 1998, and 2002 (Puget Sound River History Project, 2003; Collins & Sheikh, 2004) and National Agriculture Imagery Program (NAIP) imagery for 2006, 2008, 2009, 2011, 2013, 2015, 2017, 2019, and 2022 (U.S. Department of Agriculture, 2006-2022). All imagery has a pixel resolution of 1x1m or finer. Data is stored in a geopackage, ClayBanksRiverHillslopePlanformMaps.gpkg. Within the geopackage, layers are organized as ‘YYYY_FeatureLabel’ where YYYY denotes the year of reference followed by feature label including: 1)‘ActiveHillslope’: polygons of individual landslide deposits active at or between imagery dates. We identify active landslides based upon a visual transition from vegetated to exposed sediment or apparent sediment displacement between imagery time periods. 2) ‘MainRiverChannel’: a polygon mapping the area of continuous water coverage at the time of image acquisition. 3)‘FloodplainCorridor’: a polygon of the floodplain corridor including the extent of high flow fluvial deposits and channel scars. 4)‘VegetatedBars’: polygons noting regions of shrubs and small trees occupying the floodplain corridor. When plotted with the floodplain corridor, these features help indicate preferential pathways of flow at high water stages. 5)‘ChannelCenterline’: a line feature which maps the flow trajectory of the main river channel. The data also include an “AverageValleyCenterline” line feature that roughly delineates the time-averaged flow trajectory across all planform maps. An additional ‘layer_styles’ layer is included for default layer coloring and style that may be used when loading data via QGIS or in Python (e.g. GeoPandas). These data are used in Ahrendt et al., (in review) to analyze planform changes in fluvial and hillslope morphology. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsemsent by the U.S. Government. References: Ahrendt, S. M., Mirus, B. B., LaHusen, S. R., Perkins, J. P. Dynamic feedbacks between river meandering and landsliding in northwestern Washington glacial terraces: submitted to JGR-Earth Surface Collins, B. D., & Sheikh, A. (2004). Historical Channel Locations of the Nooksack River. University of Washington. https://books.google.com/books?id=_b2A0AEACAAJ U.S. Department of Agriculture. (2006-2022). National Agriculture Imagery Program (NAIP): Washington State NAIP imagery. https://doi.org/10.5066/F7QN651G Puget Sound River History Project. (2003). Nooksack River orthophotos. Department of Earth and Space Sciences, University of Washington. https://riverhistory.ess.washington.edu/

Wildfire can substantially alter the hydrologic response of watersheds to rainfall, and debris-flow activity is the among the most destructive consequences of these events. To assist federal, state, and local agencies in planning for postfire hazards, the U.S. Geological Survey conducts debris-flow hazard assessments for recent wildfires.This item holds the postfire debris-flow hazard assessment for the South Fork fire event that began on or near 2024-06-17. Contents: Shapefiles.zip Zip archive of hazard modeling results. Includes shapefiles for the fire perimeter, stream segments, catchment basins, and outlet points. sfk2024-field-descriptions.txt Descriptions of the shapefile data fields. sfk2024-median-thresholds.csv Table of median rainfall thresholds as calculated over the stream segments and catchment basins. sfk2024-metadata.txt Auxiliary metadata about the fire event and implementation of the hazard assessment. Methods: The hazard assessment was designed to implement: * The "M1" debris-flow likelihood model of Staley and others (2017) * The "emergency" potential sediment volume model of Gartner and others (2014) * The debris-flow combined hazard classification scheme of Cannon and others (2010) The assessment was produced by USGS personnel running the beta version of the ocelote package. Operational personnel may have also modified stream network delineation and modeling parameters in order to ensure quality. The beta version is represented by the ocelote commits prior to the v1.0.0 release. The ocelote source repository can be found here: https://code.usgs.gov/ghsc/lhp/ocelote References: Cannon, S. H., Gartner, J. E., Rupert, M. G., Michael, J. A., Rea, A. H., and Parrett, C. (2010). Predicting the probability and volume of postwildfire debris flows in the intermountain western United States. Bulletin, 122(1-2), 127-144. Gartner, J. E., Cannon, S. H., and Santi, P. M. (2014). Empirical models for predicting volumes of sediment deposited by debris flows and sediment-laden floods in the transverse ranges of southern California. Engineering Geology, 176, 45-56. Staley, D. M., Negri, J. A., Kean, J. W., Laber, J. L., Tillery, A. C., and Youberg, A. M. (2017). Prediction of spatially explicit rainfall intensity–duration thresholds for post-fire debris-flow generation in the western United States. Geomorphology, 278, 149-162.

This data release includes 2014 time-series data from three debris-flow monitoring stations at Chalk Cliffs in Chaffee County, Colorado, USA. The data were collected to help identify the triggering conditions, magnitude, and mobility of debris flows at the site. The three stations are located sequentially along a channel draining the 0.3 km^2 study area. The Upper, Middle, and Lower stations have respective drainage areas of 0.06, 0.16, and 0.24 km^2. The location (UTM zone 13) of each station is: 396826E/4287851N (Upper), 396893E/ 4287815N (Middle), and 396929E/4287712N (Lower). See also “ChalkStationLocations.jpg” in the README.zip file. The 2014 data includes three types of time series: (1) 1-minute time series of rainfall recorded by tipping bucket rain gages at each station, (2) 10-Hz time series of flow stage recorded by laser distance meters at each station, and (3) 333-Hz time series of ground vibrations and basal normal force at the Upper station only. Ground vibrations were recorded by two 4.5 Hz triaxial geophones separated by 18 m along the channel. Basal normal force was recorded by a 232 cm^2 force plate installed in the bedrock channel bed directly beneath the laser distance meter. The 10-Hz stage data is collected only when it is raining due to data storage limitations. Similarly, the 333-Hz ground motion and force data are provided only during significant flow events. These events occurred on 4 July 2014, 31 July 2014, 1 August 2014, 4 August 2014, and 6 August 2014. The first three events are primarily debris flows and the last two events are debris floods. Note that the rain gage at the Lower station, which is partially shielded by a near-vertical cliff, is used primarily as a trigger for sampling 10-Hz stage data rather than providing an accurate representation of rainfall at the station. Details of the sensors and photos of each station are contained in the “README.zip” file. The file also contains formulas for (1) converting the distance between the laser and the flow surface (or stationary bed surface) to stage above the datum for each station, and (2) converting the raw voltage readings from the geophones and force plate transducer into engineering units of ground velocity and normal force, respectively. Additional details of the study are provided in the journal articles: McCoy, S. W., J. W. Kean, J. A. Coe, G. E. Tucker, D. M. Staley, and T. A. Wasklewicz (2012), Sediment entrainment by debris flows: In situ measurements from the headwaters of a steep catchment, J. Geophys. Res., 117, F03016, doi:10.1029/2011JF002278. Kean, J. W., J. A. Coe, V. Coviello, J. B. Smith, S. W. McCoy, and M. Arattano (2015), Estimating rates of debris flow entrainment from ground vibrations, Geophys. Res. Lett., 42, doi:10.1002/2015GL064811.

This data release includes 2014 time-series data from three debris-flow monitoring stations at Chalk Cliffs in Chaffee County, Colorado, USA. The data were collected to help identify the triggering conditions, magnitude, and mobility of debris flows at the site. The three stations are located sequentially along a channel draining the 0.3 km^2 study area. The Upper, Middle, and Lower stations have respective drainage areas of 0.06, 0.16, and 0.24 km^2. The location (UTM zone 13) of each station is: 396826E/4287851N (Upper), 396893E/ 4287815N (Middle), and 396929E/4287712N (Lower). See also “ChalkStationLocations.jpg” in the README.zip file. The 2014 data includes three types of time series: (1) 1-minute time series of rainfall recorded by tipping bucket rain gages at each station, (2) 10-Hz time series of flow stage recorded by laser distance meters at each station, and (3) 333-Hz time series of ground vibrations and basal normal force at the Upper station only. Ground vibrations were recorded by two 4.5 Hz triaxial geophones separated by 18 m along the channel. Basal normal force was recorded by a 232 cm^2 force plate installed in the bedrock channel bed directly beneath the laser distance meter. The 10-Hz stage data is collected only when it is raining due to data storage limitations. Similarly, the 333-Hz ground motion and force data are provided only during significant flow events. These events occurred on 4 July 2014, 31 July 2014, 1 August 2014, 4 August 2014, and 6 August 2014. The first three events are primarily debris flows and the last two events are debris floods. Note that the rain gage at the Lower station, which is partially shielded by a near-vertical cliff, is used primarily as a trigger for sampling 10-Hz stage data rather than providing an accurate representation of rainfall at the station. Details of the sensors and photos of each station are contained in the “README.zip” file. The file also contains formulas for (1) converting the distance between the laser and the flow surface (or stationary bed surface) to stage above the datum for each station, and (2) converting the raw voltage readings from the geophones and force plate transducer into engineering units of ground velocity and normal force, respectively. Additional details of the study are provided in the journal articles: McCoy, S. W., J. W. Kean, J. A. Coe, G. E. Tucker, D. M. Staley, and T. A. Wasklewicz (2012), Sediment entrainment by debris flows: In situ measurements from the headwaters of a steep catchment, J. Geophys. Res., 117, F03016, doi:10.1029/2011JF002278. Kean, J. W., J. A. Coe, V. Coviello, J. B. Smith, S. W. McCoy, and M. Arattano (2015), Estimating rates of debris flow entrainment from ground vibrations, Geophys. Res. Lett., 42, doi:10.1002/2015GL064811.