Beget, J.E.
Larsen, J.F.
Neal, C.A.
Nye, C.J.
Schaefer, J.R.
2005
Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska
vector digital data
Report of Investigation
RI 2004-3
Fairbanks, AK
State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys
1 sheet, scale 1:150,000
http://www.dggs.dnr.state.ak.us/pubs/pubs?reqtype=citation&ID=7042
This dataset consists of the vector digital GIS files that were used to create sheet 1 of the "Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska" (DGGS RI 2004-3). The map area is centered around Okmok Volcano, on eastern Umnak Island. The data includes volcano-hazard zones for ballistics, ash accumulation, pyroclastic flows, floods and lahars, and debris avalanches. Also included in the dataset are roads, trails, seismic station locations, continuous GPS station locations, creeks, and the location of the Fort Glenn airstrip.
This dataset was created to illustrate, at a scale of 1:150,000 the approximate location of volcanic hazard zones around Okmok Volcano.
The basemap for the vector files included in this dataset is a georeferenced shaded relief tiff image whose metadata can be found in the file RI2004-3_basemap.faq.html. The 18 files listed below are available in both MapInfo TAB and ESRI shapefile format. Attribute information for the following layers (entities) is included in this metadata file under the "Entity_and_Attribute_Information" section. Each layer is listed and described in detail under its own heading starting "Entity_Type_Label." Listed here are the file names and a brief description of their content:
>OKConeA5km_polyline approximate hazard zone for ballistics from Cone A
>OKContinuousGPS_point location of continuous GPS stations
>OKCraterCrFlood_polyline approximate limits of Crater Creek Flood hazard zone
>OKCreeks_polyline major creeks around Okmok Volcano
>OKDebrisArrows_polyline arrows showing the approximate location and direction of flow of debris avalanches that could occur on the steep flanks of Tulik Volcano and the inner caldera walls of Okmok Volcano
>OKDebrisTDA_polyline mapped boundary of a prehistoric debris avalanche from Tulik Volcano
>OKDebrisTulik_region approximate hazard zone for debris avalanches with source areas on the steep flanks of Tulik Volcano
>OKFlood_region approximate location of flood and lahar hazards
>OKFtGlennAir_point location of the Fort Glenn airstrip
>OKHazMapBdry_polyline outline of the basemap
>OKLatLines_polyline four 10-minute latitude lines in the map area
>OKLongLines_polyline four 20-minute longitude lines in the map area
>OKPFsurge_polyline approximate location of pyroclastic flow and surge hazard zone
>OKRim15km_polyline approximate limit of significant ashfall, located 15 kilometers from the caldera rim
>OKRim30km_polyline approximate maximum extent of pyroclastic flows, sures, and lateral blasts during a very large eruption, located 30 kilometers from the caldera rim
>OKroad_polyline unmaintained dirt roads
>OKSeisStat_point location of seismic stations
>OKtrail_polyline unmaintained trails
2004
ground condition
as needed
-168.7576
-167.5153
53.7312
53.1099
-168.7262 53.7312, -167.5153 53.7020, -167.5634 53.1099, -168.7576 53.1384
ISO 19115 Topic Category
geoscientificInformation
none
Aleutian Arc
Volcanoes
none
Aleutian Islands
Fort Glenn
Fox Islands
Okmok, Mount
Okmok Caldera
Umnak Island
This report, map, and/or dataset are available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. User specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys.
State of Alaska, Division of Geological & Geophysical Surveys
Alaska Volcano Observatory Geologist III
mailing and physical address
3354 College Road
Fairbanks
AK
99709-3707
USA
(907) 451-5010
Not Available
(907) 451-5050
dggspubs@alaska.gov
8 am to 4:30 pm Monday through Friday, except State holidays
Please address all comments or questions to the e-mail address above whenever possible.
This dataset was compiled by the authors with funds from the Alaska Volcano Observatory, a joint program of the U.S. Geological Survey, the University of Alaska Fairbanks-Geophysical Institute, and the Alaska Division of Geological & Geophysical Surveys.
This dataset was produced using MapInfo version 6.5 GIS software, then converted to ESRI shapefiles using MapInfo's universal translator. Data is available in both MapInfo TAB and ESRI shapefile formats.
Attributes in this dataset consist of GPS and seismic station names and locations, latitude and longitude line labels, and creek names. The accuracy was checked by plotting the attributes as labels in a GIS, then checking the label against the source information. Seismic and GPS station locations and names were checked using the original source data. The latitude and longitude line labels were checked by displaying them in GIS and comparing the attribute value to the actual location. The creek labels were plotted then compared to the USGS 1:250,000-scale topographic map of Umnak Island. Creek names were also derived and visually checked from Byers, F.M., 1959, Geology of Umnak and Bogoslof Islands, Aleutian Islands, Alaska: U.S. Geological Survey Bulletin 1028-L, p. 167-369.
The latitude and longitude attributes of the seismic stations and GPS station files were reformatted so that the column labels were consistent and that both sets of data are reported in decimal degrees, WGS84 datum.
This dataset includes preliminary information pertaining to the volcanic hazards at Okmok Volcano, Umnak Island, Alaska.
The accuracy of the estimated extent of any of the volcanic hazard zones should not be confused with the horizontal accuracy of the GIS data file. For example, the 5 kilometer circle drawn around cone A for ballistics hazards is positionally accurate to about 550 meters, based on the estimated "center" of cone A, however, ballistics could possibly travel much shorter or much longer distances, depending on the eruption magnitude (see text for details of each eruption hazard, DGGS RI2004-3). Most data layers were digitized on the shaded relief image OKhazbase.tiff, which has a horizontal accuracy of 60 meters (see metadata file RI2004-3_basemap_meta.txt) Each GIS layer is listed below with a brief description of its horizontal accuracy.
OkmokConeA5km_polyline A 5 km circle was generated around the center point of Cone A. The center of cone A was approximated visually from the georeferenced shaded relief basemap image (OKhazbase.tiff). Accuracy is approximately 550 meters, which is the vent diameter. Cone A center (x,y)deg = (-168.2415, 53.3992); (x,y)meters = (683,393E, 5,920,230N).
OKContinuousGPS_point Continuous GPS station locations are accurate to approximately 1 centimeter.
OKCraterCrFlood_polyline This approximated hazard zone was sketched from the shaded relief image basemap and is based on field evidence of drainage patterns of lahars and floods down Crater Creek over the last approximately 2,000 years.
OKCreeks_polyline Creeks were originally digitized from the USGS 1:250,000-scale georeferenced DRG topographic map of Umnak Island. The creeks were reprojected in MapInfo version 6.0 from the raster topo base of UTM NAD27 to UTM WGS84 to match the projection of the shaded relief basemap (OKhazbase.tiff). After reprojection the creeks were hand-edited in GIS and required adjustments up to 150 meters to fit the shaded relief basemap (OKhazbase.tiff).
OKDebrisArrows_polyline Debris arrows are randomly placed on the steep flanks of Tulik Volcano and the inner caldera wall of Okmok Volcano.
OKDebrisTDA_polyline This boundary is based on field geologic mapping at a scale of 1:63,360 and photo-interpretation resulting in a horizontal accuracy of about 500 meters.
OKDebrisTulik_region This generalized boundary is based in part on the extent of the prehistoric debris avalanche at Tulik Volcano (file OKDebrisTDA).
OKFlood_region Flood and lahar hazard zones were sketched from drainage patterns apparent on the Landsat7 GeoTIFF L72077023_023320000817_B80 of Umnak Island, acquired on 17 August 2000. The file was converted to red band 5, green band 4, and blue band 2 to enhance drainage patterns. Drainages with headwaters on the high flanks of the volcano are portrayed.
OKFortGlennAir_point Location derived from USGS 1:250,000-scale Umnak Island quadrangle DRG topographic map. Accuracy approximately 150 meters.
OKHazMapBdry_polyline Outline of OKhazbase.tiff, accurate to pixel size of OKhazbase.tiff (30 meters).
OKLatLines_polyline Generated in GIS from decimal degree end points to an accuracy of 5 decimal points, or approximately 1 meter.
OKLongLines_polyline Generated in GIS from decimal degree end points to an accuracy of 5 decimal points, or approximately 1 meter.
OKPFsurge_polyline Centered 10 kilometers around cone A (cone A center accuracy about 550 meters) with an approximate 17 kilometer extension downslope out through the breach in the caldera.
OKRim15km_polyline The approximate diameter of the somewhat circular caldera is 10 kilometers, therefore a 20-kilometer circle was generated in a GIS around the approximate center of the caldera. The center of the caldera was approximated visually in a GIS from the georeferenced shaded relief basemap (OKhazbase.tiff). Accuracy is approximately 1,500 meters. For this purpose, the caldera center was positioned at (x,y)deg = (-168.4372, 53.4348); (x,y)meters = (670,243E, 5,923,700N).
OKRim30km_polyline The approximate diameter of the somewhat circular caldera is 10 kilometers, therefore a 35 kilometer circle was generated in a GIS around the approximate center of the caldera. The center of the caldera was approximated visually in a GIS from the georeferenced shaded relief basemap (OKhazbase.tiff). Accuracy is approximately 1,500 meters. For this purpose, the caldera center was positioned at (x,y)deg = (-168.4372, 53.4348); (x,y)meters = (670,243E, 5,923,700N)
OKroad_polyline Roads were digitized from the USGS 1:250,000-scale Umnak Island quadrangle DRG topographic map, then reprojected from UTM NAD27 to UTM WGS84 in MapInfo version 7.0. Accuracy is approximately 150 meters.
OKSeisStation_point Seismic stations were located with hand-held GPS units (accuracy less than 15 meters) except OKCD, OKFG, and OKCE, which were located with differentially corrected Trimble GPS units with an accuracy of less than 1 centimeter.
OKtrail_polyline Trails were digitized from the USGS 1:250,000-scale Umnak Island quadrangle DRG topographic map, then reprojected from UTM NAD27 to UTM WGS84 in MapInfo version 7.0. Accuracy is approximately 150 meters.
Geologic field investigations were conducted by the authors to determine the eruptive history and the geographic extent of volcanic deposits at Okmok Volcano. Based on these field investigations and the knowledge of volcanic events at other volcanoes, the volcano hazard zones were determined for Okmok Volcano. Hazard zones were digitized in a GIS using the shaded relief image (OKhazbase.tiff) as a guide. Flood and lahar hazard zones were sketched from drainage patterns apparent on the Landsat7 GeoTIFF L72077023_023320000817_B80 of Umnak Island, acquired on 17 August 2000. The file was converted to red band 5, green band 4, and blue band 2 to enhance drainage patterns.
200409
State of Alaska, Division of Geological & Geophysical Surveys
Janet R. Schaefer
Alaska Volcano Observatory, Geologist III
mailing and physical address
3354 College Road
Fairbanks
AK
99709-3707
USA
(907) 451-5010
Not available
(907) 451-5050
dggspubs@alaska.gov
8 am to 4:30 pm Monday through Friday, except State holidays
Please address all comments or questions to the e-mail address above whenever possible.
Universal Transverse Mercator
2
0.9996
-171.0000
0.0000
500000.0000
0.0000
coordinate pair
0.01
0.01
meters
WGS 1984
WGS 1984
6378137.0000
298.257224
OKConeA5km_polyline.shp
One polyline object representing a 5-kilometer-diameter circle around cone A, centered on (x,y)deg = (-168.2415, 53.3992); (x,y)meters = (683,393E, 5,920,230N).
DGGS RI 2004-3
OKConeA5km_polyline
OKContinuousGPS_point.shp
Three data points, each with station name, latitude, longitude, and elevation. Latitude and longitude have a WGS84 datum; elevation is in meters.
Data provided by Jeff Freymueller, UAF Geophysical Institute, in September 2001, in cooperation with the Alaska Volcano Observatory.
OKContinuousGPS_point
station
Continuous GPS station name
Alaska Volcano Observatory
List of station names
longwgs84
longitude value of continuous GPS station location in decimal degrees using the WGS84 datum
Alaska Volcano Observatory
longitude value
200109
200109
1 centimeter
GPS data was collected using a Trimble GPS unit and post-processed by differential correction data from a base station at Fort Glenn.
latwgs84
latitude value of continuous GPS station location in decimal degrees using the WGS84 datum
Alaska Volcano Observatory
latitude value
200109
200109
1 centimeter
GPS data was collected using a Trimble GPS unit and post-processed by differential correction data from a base station at Fort Glenn.
elev_meters
elevation in meters above mean sea level of continuous GPS station using the WGS84 datum
Alaska Volcano Observatory
elevation value
200109
200109
1 centimeter
GPS data was collected using a Trimble GPS unit and post-processed by differential correction data from a base station at Fort Glenn.
OKCraterCrFlood_polyline.shp
One polyline object representing the approximate limits of the Crater Creek flood hazard zone.
DGGS RI 2004-3
OKCraterCrFlood_polyline
OKCreeks_polyline.shp
52 polyline objects representing major drainages around Okmok Volcano.
USGS Umnak Island 1:250,000-scale topographic map
OKCreeks_polyline
CreekName
Name of the creek as derived from USGS Umnak Island 1:250,000-scale topographic map and Byers, F.M., 1959, Geology of Umnak and Bogoslof Islands, Aleutian Islands, Alaska: U.S. Geological Survey Bulletin 1028-L.
Byers, F.M., 1959, Geology of Umnak and Bogoslof Islands, Aleutian Islands, Alaska: U.S. Geological Survey Bulletin 1028-L; and USGS 1:250,000-scale topographic basemap series, Umnak Island quadrangle, Alaska.
Not all line objects have creek names. Major creeks are named, others are unnamed.
OKDebrisArrows_polyline.shp
20 polyline objects. 20 randomly placed arrows indicating source regions for rockfalls and debris avalanches on the steep slopes of Tulik Volcano and the inner caldera walls of Okmok Volcano.
DGGS RI 2004-3
OKDebrisArrows_polyline
OKDebrisTDA_polyline.shp
One polyline object. Mapped boundary of a prehistoric debris avalanche from Tulik Volcano.
DGGS RI 2004-3
OKDebrisTDA_polyline
OKDebrisTulik_region.shp
One region object. Approximate hazard zone for debris avalanches with source areas on the steep flanks of Tulik Volcano.
DGGS RI 2004-3
OKDebrisTulik_region
OKFlood_region.shp
One region object. Approximate location of flood and lahar hazards.
DGGS RI 2004-3
OKFlood_region
OKFtGlennAir_point.shp
One point object. Approximate location of Fort Glenn airstrip.
DGGS RI 2004-3
OKFtGlennAir_point
OKHazMapBdry_polyline.shp
One polyline object. Outline of basemap OKhazbase.tiff.
DGGS RI 2004-3
OKHazMapBdry_polyline
OKLatLines_polyline.shp
4 line objects. 10-minute lines of latitude covering the map area.
DGGS RI 2004-3
OKLatLines_polyline
LatDMSWGS84
Latitude in degrees, minutes, seconds
DGGS RI 2004-3
values of latitude
OKLongLines_polyline.shp
4 line objects. 20-minute lines of latitude covering the map area.
DGGS RI 2004-3
OKLongLines_polyline
LongDMSWGS84
Longitude in degrees, minutes, seconds
DGGS RI 2004-3
values of longitude
OKPFsurge_polyline.shp
One polyline object. Approximate location of pyroclastic flow and surge hazard zone.
DGGS RI 2004-3
OKPFsurge_polyline
OKRim15km_polyline.shp
One polyline object. Approximate limit of significant ashfall, located 15 kilometers from the caldera rim.
DGGS RI 2004-3
OKRim15km_polyline
OKRim30km_polyline.shp
One polyline object. Approximate maximum extent of pyroclastic flows, surges, and lateral blasts during a very large eruption, located 30 kilometers from the caldera rim.
DGGS RI 2004-3
OKRim30km_polyline
OKroad_polyline.shp
Two polyline objects. Unmaintained dirt roads.
Digitized from USGS Umnak Island 1:250,000-scale topographic map
OKroad_polyline
OKSeisStat_point.shp
12 points. Latitude, longitude, and station name of 12 seismic stations around Okmok Volcano.
Alaska Volcano Observatory
OKSeisStat_point
station
seismic station name
Alaska Volcano Observatory
List of station names
longwgs84
longitude value of seismic station location in decimal degrees using the WGS84 datum
Alaska Volcano Observatory
longitude value
15 meters
For sites OKFG, OKCD, and OKCE, the GPS data was collected using a Trimble GPS unit and post-processed by differential correction data from a base station at Fort Glenn, resulting in an accuracy of less than 1 centimeter. All others were reported from a hand-held GPS unit with a NAD27 datum, then converted to the WGS84 datum using MapInfo 7.0 GIS.
latwgs84
latitude value of seismic station location in decimal degrees using the WGS84 datum
Alaska Volcano Observatory
latitude value
15 meters
For sites OKFG, OKCD, and OKCE, the GPS data was collected using a Trimble GPS unit and post-processed by differential correction data from a base station at Fort Glenn, resulting in an accuracy of less than 1 centimeter. All others were reported from a hand-held GPS unit with a NAD27 datum, then converted to the WGS84 datum using MapInfo 7.0 GIS.
OKtrail_polyline.shp
Two polyline objects. Unmaintained trails.
Digitized from USGS Umnak Island 1:250,000-scale topographic map
OKtrail_polyline
State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys
Natural Resource Technician
mailing and physical
3354 College Road
Fairbanks
AK
99709-3707
USA
907-451-5020
None available.
907-451-5050
dggspubs@alaska.gov
8 am to 4:30 pm, Monday through Friday, except State holidays
Please view our web site (http://www.dggs.dnr.state.ak.us) for the latest information on available data. Please contact us using the e-mail address provided above when possible.
Report of Investigation 2004-3
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http://www.dggs.dnr.state.ak.us/pubs/pubs?reqtype=citation&ID=7042
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http://www.dggs.dnr.state.ak.us/pubs/pubs?reqtype=citation&ID=7042
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20080506
20080506
20091003
State of Alaska, Division of Geological & Geophysical Surveys
Janet R. Schaefer
Alaska Volcano Observatory Geologist III
mailing and physical address
3354 College Road
Fairbanks
AK
99709-3707
USA
(907) 451-5010
(907) 451-5050
dggspubs@alaska.gov
8 am to 4:30 pm, Monday through Friday, except State holidays.
Please contact us through the e-mail address above whenever possible.
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998
none
If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys.