This data release includes the detailed results from laboratory testing of colluvium and landslide deposit specimens collected from coastal bluffs near Mukilteo, Washington. The specimens were collected as part of a larger effort to characterize the potential for shallow landslide initiation along the Puget Sound Railway corridor between the cities of Everett and Seattle. The details of the specimen collection and research objectives of the study are provided in: “Assessing Landslide Potential on Coastal Bluffs near Mukilteo, Washington—Geologic Site Characterization for Hydrologic Monitoring” (doi:10.3133/ofr20161082). Laboratory experiments includes test to estimate the following properties: specific gravity, porosity, bulk and grain densities, grain-size distributions, in situ volumetric water content, liquid and plastic limits, saturated hydraulic conductivity, water-retention and unsaturated hydraulic conductivity relations, and soil strength properties. The testing of the specimens was performed by Cooper Testing Labs Inc. in Palo Alto, California, and by York Lewis at Colorado School of Mines in Golden, Colorado. The following citations relate to this data release. Mirus, B.B., Smith, J.B., Stark, Benjamin, Lewis, York, Michel, Abigail, and Baum, R.L., 2016, Assessing landslide potential on coastal bluffs near Mukilteo, Washington—Geologic site characterization for hydrologic monitoring: U.S. Geological Survey Open-File Report 2016–1082, 28 p., http://dx.doi.org/10.3133/ofr20161082. van Genuchten, MTh., 1980. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils: Soil Science Society America Journal, vol. 44, p. 892-898. Wayllace, A., and Lu, N., 2012, A transient water release and imbibitions method for rapidly measuring wetting and drying soil water retention and hydraulic conductivity functions: Geotechnical Testing Journal, vol. 35, doi: 10.1520/GTJ103596.

A hydrologic monitoring network was installed to investigate landslide hazards affecting the railway corridor along the eastern shore of Puget Sound between Seattle and Everett, near Mukilteo, Washington. During the summer of 2015, the U.S. Geological Survey installed instrumentation at four sites to measure rainfall and air temperature every 15 minutes. Two of the four sites are installed on contrasting coastal bluffs, one landslide scarred and one vegetated. At these two sites, in addition to rainfall and air temperature, volumetric water content, pore pressure, soil suction, soil temperature (via hydrologic instrumentation), and barometric pressure were measured every 15 minutes. The instrumentation was designed to supplement landslide-rainfall thresholds developed by the U.S. Geological Survey with a long-term goal of advancing the understanding of the relationship between landslide potential and hydrologic forcing along the coastal bluffs. Additionally, the system was designed to function as a prototype monitoring system to evaluate criteria for site selection, instrument selection, and placement of instruments. Two files are included with this release. A comma separated value (csv) file contains monitoring data for the time-periods described by its name, for example 20150711_20160809.csv contains data for the period between July 11, 2015 and August 9, 2016. A read-me file (readme.doc) describes the sensor naming convention used for column names in the data files. The following citation relates to a report that provides background information and is intended to accompany this data release. Smith, J.B.; Baum, R.L.; Mirus, Benjamin B.; Michel, Abigail R.; Stark, Ben, 2017, Results of Hydrologic Monitoring on Landslide-Prone Coastal Bluffs Near Mukilteo Washington: U.S. Geological Survey Open-File Report 2017-1095, 50 p., http://dx.doi.org/10.3133/ofr20171095

A hydrologic monitoring network was installed to investigate landslide hazards affecting the railway corridor along the eastern shore of Puget Sound between Seattle and Everett, near Mukilteo, Washington. During the summer of 2015, the U.S. Geological Survey installed instrumentation at four sites to measure rainfall and air temperature every 15 minutes. Two of the four sites are installed on contrasting coastal bluffs, one landslide scarred and one vegetated. At these two sites, in addition to rainfall and air temperature, volumetric water content, pore pressure, soil suction, soil temperature (via hydrologic instrumentation), and barometric pressure were measured every 15 minutes. The instrumentation was designed to supplement landslide-rainfall thresholds developed by the U.S. Geological Survey with a long-term goal of advancing the understanding of the relationship between landslide potential and hydrologic forcing along the coastal bluffs. Additionally, the system was designed to function as a prototype monitoring system to evaluate criteria for site selection, instrument selection, and placement of instruments. Two files are included with this release. A comma separated value (csv) file contains monitoring data for the time-periods described by its name, for example 20150711_20160809.csv contains data for the period between July 11, 2015 and August 9, 2016. A read-me file (readme.doc) describes the sensor naming convention used for column names in the data files. The following citation relates to a report that provides background information and is intended to accompany this data release. Smith, J.B.; Baum, R.L.; Mirus, Benjamin B.; Michel, Abigail R.; Stark, Ben, 2017, Results of Hydrologic Monitoring on Landslide-Prone Coastal Bluffs Near Mukilteo Washington: U.S. Geological Survey Open-File Report 2017-1095, 50 p., http://dx.doi.org/10.3133/ofr20171095

We performed ring shear strength testing of three specimens from a glaciolacustrine silty clay unit involved in a large landslide that occurred March 22, 2014 near the town of Oso, Washington. Ring shear tests utilized apparatus DPRI-5 at Kyoto University, Japan and test results are presented herein. We refer to the specimens as the clay, clayey silt, and silt. Some tests were performed under controlled shear stress with shear stress increased at ~0.5 kPa/s until failure and failure was permitted to continue for decimeters to meters of cumulative shear displacement. These tests were performed on unfailed material and on fault gouge that developed during failure. Other tests were performed on fault gouge under constant shear displacement rates of ~0.001–10 cm/s. Nearly all controlled shear stress tests were performed in the undrained condition (specimen chamber water lines closed) and nearly all constant shear displacement rate tests were performed in the naturally drained condition (specimen chamber water lines open). Normal stress was controlled during all tests. Cumulative shear displacement, normal stress, shear stress, pore-water pressure, and specimen thickness were continuously measured during each test. Recording of these parameters continued during hold periods after shearing ceased for many tests. Recording similarly continued during many consolidation periods that followed shearing or hold periods. Consolidation involved opening specimen chamber drainage lines to permit excess pore-water pressure (if any) to dissipate and specimen thickness to stabilize under the applied normal stress. File names indicate testing conditions. For controlled shear stress tests, file names are: specimen_”drained” or “undrained”_normal stress_”controlled shear stress”_”unfailed” or “gouge”.txt and subsequent hold and consolidation file names are: specimen_”hold” or “consolidation”_normal stress_”controlled shear stress”_ ”unfailed” or “gouge”.txt. For constant shear displacement rate tests, file names are: specimen_”drained” or “undrained”_normal stress_shear displacement rate.txt and subsequent hold and consolidation file names are: specimen_”hold” or “consolidation”_normal stress_shear displacement rate.txt. In some cases, recording was made to one file during shearing, hold, and consolidation periods. For these, file names indicate shearing conditions as described above with “hold” and/or “consolidation” appended to the end of the file name. These data support a study described in Schulz, W.H., Wang, G., Jiang, Y., Collins, B.D., and Reid, M.E., 2017, Fault gouge structure control on post-failure behavior of granular material-clay mixtures: ###################################.

This data release contains displacement and pore-water pressure data from a field experiment performed November 14, 2003, at Mount Kaba-san, Japan. This experiment generated a shallow landslide, induced by water infiltration from overhead sprinkling, that mobilized into a debris flow. More information about this experiment can be found in Ochiai and others (2004). Extensometer data recorded the ground-surface locations (displacement) and pressure transducers recorded dynamic pore-water pressures within the hillslope leading up to and through rapid failure. Data were recorded at a 100-Hz sampling frequency on a National Instruments data-acquisition system. The accompanying cross-sectional diagram (Japan_exp_cross-section.png) illustrates the general instrument configuration at the start of the experiment. Extensometers (linear position transducers) were attached to the overhead sprinkling structure and their wire cables (that extend with displacement) were attached to ground anchors downslope of the instruments. These instruments with retractable wire rope cables were manufactured by UniMeasure. Extensometer 4 had a longer wire length to better record the transition from slow sliding motion to rapid debris flow. Extensometer Model Approx. wire length range (m) 3 JX-PA-80-N11-11S-111 2 4 HX-PA-400 8 5 JX-PA-80-N11-11S-111 2 Piezometers were directly buried pressure transducers encased in custom-built cylindrical housings (43 mm in diameter, 93 mm long) with sintered filters at their bases (refer to Japan_exp_piezometer_images.jpg). The transducers within the enclosures were manufactured by Druk, model PDCR800, with a range of 70 kiloPascals (kPa) gauge pressure. Each enclosure had two sealable tubes that extended to the ground surface after burial. These tubes allowed water to be injected into the enclosure through one tube and air to escape out the other tube. This configuration enabled full water saturation of the enclosed transducer sensors, rapid pressure transmission to the sensor diaphragms, and better recording of dynamic responses during rapid failure. This data release contains the following files: (1) Metadata for this data release. (2) Data (in csv format) from the entire experiment (until about six minutes after rapid failure) downsampled to 1-Hz for ease of viewing and plotting. Time in seconds denotes time after overhead sprinkling commenced. (3) Data (in csv format) from the rapid-failure period (24620-24640 seconds) at 100-Hz to portray dynamic responses during rapid failure. (4) Image of experiment cross section showing instrument locations and landslide failure mass. (5) Images of piezometers consisting of pressure transducers and enclosures. Extensometer data is presented as raw recorded position (m) and corrected position (m) to reflect downslope, rather than oblique, displacement. Refer to Processing Steps in the metadata for more information on extensometer data corrections. Pore-pressure data is presented in recorded centimeters of head and converted to kPa. Reference cited Ochiai, H., Okada, Y., Furuya, G., Okura, Y., Matsui, T., Sammori, T., Terajima, T. and Sassa, K., 2004, A fluidized landslide on a natural slope by artificial rainfall: Landslides, v. 1, p. 211-219.

This USGS data release represents tabular data and water-level modeling files for the 16 Pahute Mesa multiple-well aquifer tests conducted from 2009–2014. The data release was produced in compliance with the new 'open data' requirements as a way to make the scientific products associated with USGS research efforts and publications available to the public. The dataset consists of 5 separate items: 1. Pumping time-series data (Tabular dataset) 2. Simplified pumping time-series data (Tabular dataset) 3. Drawdown time-series data (Tabular dataset) 4. Water-level models (Macro-enabled Excel spreadsheets) 5. SeriesSEE (Excel Add-In)

A time-lapse camera was used to document periodic reactivation of a complex landslide on a steep coastal bluff in Mukilteo, Washington. This landslide is one of four monitoring sites initiated by the U.S Geological Survey to investigate hill-slope hydrology and landslide hazards affecting the railway corridor along the eastern shore of Puget Sound between the cities of Seattle and Everett (Mirus et al., 2016; Smith et al. 2017). The camera was installed in the crown of the landslide above the main scarp facing roughly North, with a field of view that includes the head of the landslide body and a minor scarp below. The attached file ‘CameraLocation.PNG’ provides an overview figure of the landslide and the camera’s location relative to the different monitoring stations. It recorded imagery from August 19th, 2015 through May 25th, 2016. The time-lapse photos were taken three times daily (at 9 am, 12 pm, and 4 pm, PST) and stored onsite on a memory card; corresponding intervals between the photographs were 3 hours, 4 hours, and 17 hours (overnight). The time-lapse photos were compiled into a video and five periods of distinct ground movement were identified. Apparent slow and consistent slope-surface movements are recorded during these periods, but subsequent site visits suggest that these slow displacements indirectly triggered topples and debris-avalanche movements both up slope and down slope of the camera’s field of view. The approximate sizes of topples and debris avalanches were on the order of 10^5 –10^7 cubic centimetres. The video captures slope movements during the time periods of December 8–9, 2015; January 21–30, 2016; and March 9–14, 2016. In addition, the video shows two seemingly “instantaneous” events during the nights of March 23 and March 26. Each of these periods of slope movement also correspond to observed rainfall events and associated subsurface hydrologic responses documented elsewhere (Mirus et al. 2017; Smith et al. 2017). The time-lapse video can be found in the attached .mp4 file "mukilteo_timelapse_video.mp4" The individual time-lapse photos can be downloaded from the attached zip file "mukilteo_timelapse_photos.zip." More detailed information about the camera and settings used can be found in the metadata file. The following citations relate to reports that provides background information and are intended to accompany this data release. Mirus, B. B., Smith, J. B., Stark, B., Lewis, Y., Michel, A., & Baum, R. L. (2016). Assessing landslide potential on coastal bluffs near Mukilteo, Washington—Geologic site characterization for hydrologic monitoring. (U.S. Geological Survey Open-File Rep., 2016-1082, 28). Reston, VA: U.S. Geological Survey. https://doi.org/10.3133/ofr20161082 Smith, J. B., Baum, R. L., Mirus, B. B., Michel, A., & Stark, B. (2017). Results of hydrologic monitoring on landslide-prone coastal bluffs near Mukilteo, Washington (U.S. Geological Survey Open-File Rep., 2017–1095, 47 p.). Reston, VA: U.S. Geological Survey. https://doi.org/10.3133/ofr20171095 Mirus, B. B., Smith, J. B., & Baum, R. L. (2017). Hydrologic impacts of landslide disturbances: implications for remobilization and hazard persistence. Water Resources Research, 53. https://doi.org/10.1002/2017WR020842

Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of surficial sediments from Chincoteague Bay and Tom's Cove, located between Assateague Island and the Delmarva Peninsula in March/April 2014 (2014-301-FA) and October 2014 (2014-322-FA). The sampling efforts were part of a larger U.S. Geological Survey study to assess the effects of storm events on sediment distribution. The objective of this study was to characterize the sediments of Chincoteague Bay in order to create baseline conditions to incorporate with hydrodynamic and sediment transport models in order to evaluate pre- and post-storm (Hurricane Sandy) change. This report serves as an archive for sedimentological data derived from the surface sediment. Data are available for a seasonal comparison between March/April 2014 and October 2014. Downloadable data are available as Excel spreadsheets (sediment samples) and as JPEG files (maps). Additional files include: detailed results of sediment grain size analyses, and formal Federal Geographic Data Committee metadata (data downloads).

Short-term aquifer tests were conducted to estimate hydraulic properties in an alluvial aquifer. Tests included eight single-hole pumping and recovery tests and three slug tests (in a single well). These investigations were conducted in the Wet Mountain Valley, in Custer and Fremont Counties, Colorado. The U.S. Geological Survey (USGS) conducted aquifer tests in May, 2019. These aquifer tests inform the conceptual understanding of the valley-fill aquifer and serve as primary inputs to the numerical groundwater-flow model. Testing was completed in cooperation with the Upper Arkansas Water Conservancy District. This data release contains raw data from aquifer tests, water-level and pumping discharge rate measurements, well logs, graphs of the testing data, and plots of analytical solutions.

Short-term aquifer tests were conducted to estimate hydraulic properties in an alluvial aquifer. Tests included eight single-hole pumping and recovery tests and three slug tests (in a single well). These investigations were conducted in the Wet Mountain Valley, in Custer and Fremont Counties, Colorado. The U.S. Geological Survey (USGS) conducted aquifer tests in May, 2019. These aquifer tests inform the conceptual understanding of the valley-fill aquifer and serve as primary inputs to the numerical groundwater-flow model. Testing was completed in cooperation with the Upper Arkansas Water Conservancy District. This data release contains raw data from aquifer tests, water-level and pumping discharge rate measurements, well logs, graphs of the testing data, and plots of analytical solutions.