Filters: Tags: volcanic eruptions (X) > Extensions: ArcGIS Service Definition (X)
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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,
The California volcano locations, threat rank and hazard zones data release contains two shapefiles for download or use as a web map service. The California Volcanic Center Locations shapefile was created to provide a generalized location of volcano hazard sources. The California Volcano Hazard Zones shapefile was created from previously published hazard zone reports. Specific details about each file can be found in the metadata included with each file and the read-me document for this data release. Together, these files were used to define California Volcano Hazards for the GIS analysis that supports conclusions in the California's exposure to volcano hazards report. Geologists produce hazard zone maps to convey...
Categories: Data;
Types: ArcGIS REST Map Service,
ArcGIS Service Definition,
Downloadable,
Map Service;
Tags: Alpine County,
Ash,
Ballistic,
Butte County,
California,
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