Geologist
Email:
dramsey@usgs.gov
Office Phone:
360-993-8978
Fax:
360-993-8980
ORCID:
0000-0003-1698-2523
|
This geologic map database is a reproduction of U.S. Geological Survey Miscellaneous Investigations Map I–2362: “Geologic Map and Structure Sections of the Clear Lake Volcanics, Northern California” (Hearn, Donnelly-Nolan, and Goff, 1995). The database consists of a geologic map, three structural cross sections and a table of petrographic data for each map unit by mineral type, abundance, and size. The Clear Lake Volcanics are in the California Coast Ranges about 150 km north of San Francisco. This Quaternary volcanic field has erupted intermittently since 2.1 million years ago. This volcanic field is considered a high-threat volcanic system (Ewert and others, 2005). The adjacent Geysers geothermal field, the largest...
Tags: California,
Clear Lake,
Geochemistry,
Geography,
Geomorphology, All tags...
Lake County,
Land Use Change,
Mount Konocti,
Sonoma County,
Stratigraphy,
The Geysers,
USGS Science Data Catalog (SDC),
United States of America,
climatologyMeteorologyAtmosphere,
earth sciences,
geologic maps,
geology,
health,
volcanoes,
volcanology, Fewer tags
|
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...
Tags: California,
Klamath National Forest,
Lava Beds National Monument,
Medicine Lake,
Medicine Lake volcano, All tags...
Modoc,
Modoc National Forest,
Shasta-Trinity National Forest,
Siskiyou,
USGS Science Data Catalog (SDC),
Volcanic ash,
Volcanology,
hazards,
volcanic activity,
volcanic eruption prediction,
volcanic rocks,
volcanology, Fewer tags
|
There are 161 active volcanoes in the U.S. and its territories. These volcanoes pose differing degrees of risk to people and infrastructure because of differences in their eruptive styles and geographic locations. This layer shows the areas near volcanic vents that could be affected by proximal volcano hazards, including ballistics (airborne rocks from explosions), pyroclastic density currents, lava flows, debris avalanches, lahars (mudflows), and heavy ashfall, as well as areas downstream that could be affected by distal lahars (see the USGS Volcano Hazards Program Glossary for descriptions of these processes: https://www.usgs.gov/glossary/volcano-hazards-program-glossary). These areas are labelled with their corresponding...
Tags: Alaska,
America Samoa,
Arizona,
California,
Colorado, All tags...
Hawaii,
Idaho,
Nevada,
New Mexico,
Northern Mariana Islands,
Oregon,
USGS Science Data Catalog (SDC),
United States,
Utah,
Volcanology,
Washington,
geoscientificInformation,
risk assessment,
volcanic activity,
volcanology, Fewer tags
|
The 2018 eruption of Kīlauea Volcano on the Island of Hawaiʻi saw the collapse of a new, nested caldera at the volcano’s summit, and the inundation of 35.5 square kilometers (13.7 square miles) of the lower Puna District with lava. Between May and August, while the summit caldera collapsed, a lava channel extended 11 kilometers (7 miles) from fissure 8 in Leilani Estates to Kapoho Bay, where it formed an approximately 3.5-square-kilometer (1.4-square-mile) lava delta along the coastline. Rapidly-deployed remote sensing techniques were vital in monitoring these events. Following the eruption, the U.S. Geological Survey (USGS) contracted the acquisition of rigorous airborne lidar surveys of Kīlauea Volcano's summit,...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: ALS,
DEM,
East Rift Zone,
Geography,
Geomorphology, All tags...
Geophysics,
HI,
Hawaiʻi,
Hydrology,
Kapoho Bay,
Kīlauea Volcano,
Land Use Change,
Leilani Estates,
Marine Geology,
Puna District,
Puʻu ʻŌʻō,
Remote Sensing,
Sedimentology,
Seismology,
Soil Sciences,
Stratigraphy,
Structural Geology,
USA,
USGS Science Data Catalog (SDC),
Volcanology,
airborne laser scanning,
bare earth,
digital elevation model,
elevation,
elevation,
geomorphology,
geoscientificInformation,
hillshade,
lidar,
light detection and ranging,
near infrared,
shaded relief,
topography,
volcanic,
volcano, Fewer tags
|
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, All tags...
Colorado,
Geochemistry,
Gunnison,
Lava flow,
Pyroclastic rock,
Rhyolite,
San Juan,
Tuff,
USGS Science Data Catalog (SDC),
United States,
Volcanic breccia,
Volcanology,
Welded tuff,
caldera,
faulting (geologic),
faulting (geologic),
geoscientificInformation,
volcanic activity,
volcanic activity,
volcanic eruptions,
volcanic features,
volcanic rocks,
volcanic rocks,
volcanology,
volcanology, Fewer tags
|
View more...
|
