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The Taupo Volcanic Zone (TVZ), New Zealand, is the most productive area of explosive silicic volcanism in the world. Faulted early and middle Pleistocene volcanic products are generally concealed beneath voluminous, generally unfaulted, younger volcanic products. An exception is the southeast margin of the TVZ where the two parallel, northeast-trending Paeroa and Te Weta Fault blocks expose Quaternary volcanic products consisting predominantly of caldera-related, rhyolitic ignimbrites and lacustrine sediments. The Taupo-Reporoa Basin is situated along the eastern part of the map area, and its northernmost part underwent collapse to form Reporoa Caldera. The Paeroa Fault block is the largest exposed fault block within...
A total of 100 samples were collected from two proximal sections of Keanakākoʻi, Tephra unit D deposits. Samples were analyzed on Microtrac CAMSIZER® P4 and X2 instruments for grain size and shape data in the USGS Hawaiian Volcano Observatory (HVO) tephra lab. Data release includes sample descriptions, half phi grain size distributions, and statistical output from DECOLOG deconvolution modeling of grain size distributions. Grain size is reported using the sieve compatible Xcmin parameter (CAMSIZER® manual, 2020). Data of 2D shape parameter means of sphericity, Krumbein roundness and compactness of samples as well as for half phi grain size bins at 4, 3, 2, 1, 0, and -1 phi are also included. Please refer to associated...
Categories: Data;
Tags: Camsizer,
Grain shape,
Grain size,
Hawaii Volcanoes National Park,
Kīlauea Volcano,
Medicine Lake volcano (MLV) is a very large shield-shaped volcano located in northern California where it forms part of the southern Cascade Range of volcanoes. It has erupted hundreds of times during its half-million-year history, including nine times during the past 5,200 years, most recently 950 years ago. This record represents one of the highest eruptive frequencies among Cascade volcanoes and includes a wide variety of different types of lava flows and at least two explosive eruptions that produced widespread fallout. Compared to those of a typical Cascade stratovolcano, eruptive vents at MLV are widely distributed, extending 55 km north-south and 40 km east-west. The total area covered by MLV lavas is >2,000...
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 rock (e.g., Bessette-Kirton et al., 2019a). To better understand the characteristics of Maria-triggered landslides, debris flows, and materials in which landslides occurred, we performed reconnaissance-level studies of 118 landslides, 46 soil exposures generally within landslide scars, 24 saprolite exposures, and 37 rock exposures....
LiDAR scans were taken using a tripod mounted Riegl VZ-400 scanning LiDAR. The tripod was set up such that the scanner was between 1.5 and 2.5 m tall. The VZ-400 is a near infrared (1550 nm) scanner. Geometric control was achieved using a pair of Trimble RB GPS antennae, one mounted on the LiDAR scanner (rover) and the other setup as a base station. Before taking a LiDAR scan, the VZ-400 would use the GPS to fix a real time kinematic (RTK) solution for the scanner’s location and then use that position (scan position) as a reference for LiDAR returns. Post processing was done using RIScan-Pro version 2 (scanner specific software). Also, in post-processing, overlapping areas of point clouds were merged and inaccuracies...
The Harrat Rahat volcanic field, located in the west-central part of the Kingdom of Saudi Arabia, is the largest of 15 harrats (Arabic for 'volcanic field') hosted within the Arabian plate. Harrat Rahat is 50 to 75 km wide (east-west) and 300 km long (north-south), covering an area of approximately 20,000 square kilometers and encompassing more than 900 observable vents. The overall map area and its dataset show the volcanic geology of the northern part (about 3,340 square kilometers) of Harrat Rahat, at a scale of 1:75,000. Two additional map areas and their feature classes highlight areas of interest at 1:25,000 scale. Northern Harrat Rahat is of interest owing to the location of the city of Al-Madinah Al-Munawarah...
Categories: Data;
Types: ArcGIS REST Map Service,
ArcGIS Service Definition,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Al-Madinah Al-Munawarah,
Basalt,
Benmoreite,
Harrat Rahat volcanic field,
Lava flow,
This dataset contains Unoccupied Aircraft Systems (UAS) footage from the 2018 summit collapse of Kīlauea Volcano, Island of Hawai‘i. The intrusion of magma into Kīlauea’s lower East Rift Zone triggered draining of the summit lava lake and magma withdrawal from the shallow reservoir. This resulted in 62 subsequent collapse events at the summit between May and early-August 2018. Each collapse event released energy equivalent to a magnitude-5.3 earthquake. The total collapse volume was about 0.8 km^3, with subsidence of more than 500 m in some places. There are 73 UAS videos in this publication, recorded from May 19 to September 5, which have been separated into subpages by month. Sub-pages for each month also contain...
Visible/near-infrared (VNIR) and mid-infrared (MIR) spectral library composed of twenty natural tephra samples from ten volcanic sources that span a range of compositions and components. The bulk, glass, and mineral phase compositions of each sample have been measured and VNIR and MIR spectra from four size fractions of each sample were collected. The VNIR spectral library has been expanded (ed. 2) to twenty-two samples.
This data release contains gridded estimates of postfire debris flow probability and magnitude for six different rainfall and wildfire scenarios in southern California. The scenarios represent the present and possible future precipitation and fire regimes for the region. The results are provided for 1 km2 cells across the study area. The data release accompanies the journal article Kean, J.W. and Staley, D.M. (2021). Forecasting the frequency and magnitude of postfire debris flow across southern California, Earth's Future, 2020EF001735.
This report evaluates the volcano-related hazards, including regional mafic lava flows, silicic lava domes, pyroclastic flows, lahars, and volcanic ash, of the Lassen region, California, which is here defined as an area between the Pit River on the north and the southern limit of active Cascade volcanism, approximately 5–10 km south of the southern boundary of Lassen Volcanic National Park. Most active volcanism occurs in a zone about 40 km wide between Viola on the west and the eastern boundary of Caribou Wilderness Area, but sparser volcanism in the west extends the width of this zone to about 75 km. All vents and deposits known or estimated to be less than 100,000 years are identified and considered in establishing...
This geodatabase contains all the geologic map information for the Geologic Map of the San Juan caldera cluster, southwestern Colorado and is part of U.S. Geological Survey Geologic Investigations Map Series I-2799. The San Juan Mountains are the largest erosional remnant of a composite volcanic field that covered much of the southern Rocky Mountains in middle Tertiary time. The San Juan field consists mainly of intermediate-composition lavas and breccias, erupted about 35-30 Ma from scattered central volcanoes (Conejos Formation) and overlain by voluminous ash-flow sheets erupted from caldera sources. In the central San Juan Mountains, eruption of at least 8,800 km3 of dacitic-rhyolitic magma as nine major ash...
Categories: Data;
Types: ArcGIS REST Map Service,
ArcGIS Service Definition,
Downloadable,
Map Service;
Tags: Andesite,
Ash-flow tuff,
Basalt,
Central San Juan Caldera Cluster,
Central San Juan Mountains,
This data release contains data summarizing observations within and adjacent to the Woodbury Fire, which burned from 8 June to 15 July 2019. In particular, this monitoring data was focused on debris flows in burned and unburned areas. Rainfall data (1_Woodbury_Rainfall.zip) are contained in comma-separated value (CSV) files named “Wdby_Rainfall” appended with the names of 3 rain gages: B2, B6, and Reavis. This is time-series data where the total rainfall in millimeters is recorded at each timestamp. The location of each rain gage is listed as a latitude/longitude in each file. Pressure data from absolute (i.e. not vented) pressure transducers (2_Woodbury_Pressure.zip), which can be used to constrain the...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Arizona,
Debris flow,
Geomorphology,
Hydrology,
Superstition Mountains SW,
The Coachella paleoseismic site is located on the San Andreas Fault along the northeast edge of the Coachella Valley in southern California, southwest of the intersection of Dillon Road and Avenue 44. In 2006, three benched trenches were excavated across the fault zone as part of an Alquist-Priolo fault investigation study by a private geotechnical firm (see APSI_003361 at https://maps.conservation.ca.gov/cgs/informationwarehouse/apreports/). These trenches exposed a thick section of latest Holocene lacustrine, alluvial, and shoreline deposits. Only the central and eastern trenches exposed faulting so paleoseismic investigations were confined to those two trenches. In the central trench (T1), we photographed and...
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