Jane F. Denny 2003 raster Woods Hole, MA U.S. Geological Survey Bear Lake is a tectonic lake that has existed for at least several hundred thousand years. The lake basin is a relatively simple half graben, a spoon-shaped depression tilted toward the main fault on the east side of the lake. The U.S. Geological Survey, in cooperation with researchers from several universities, has been studying the sediments of Bear Lake since 1996. The general purpose of this effort is to reconstruct past limnological conditions and regional climate on a range of timescales, from hundreds of years to hundreds of thousands of years. This research relates to a variety of human concerns, including water usage in the Bear River basin. Past work has included several coring operations, a seismic-reflection survey, sediment-trap deployments, a barge-mounted drilling operation with the GLAD800 drill rig, and a variety of other studies. The objectives of the September, 2002 operations, preliminarily reported here, were (1) to compile a detailed bathymetric map of the lake using swath-mapping techniques, in order to provide baseline data for a variety of applications and studies, and (2) to complete a sidescan-sonar survey of the lake, providing a nearly complete acoustic image of the lake floor. Limited amounts of subbottom acoustic-reflection data (CHIRP) were also collected, along with samples of lake-floor sediments representative of different kinds of backscatter patterns. These surveys followed an earlier subbottom acoustic-reflection survey (1997), using boomer and 3.5 kHz systems (S. M. Colman, unpublished data). JPG images of each seismic line were generated in order to incorporate images of the seismic data into Geographic Information System (GIS) projects and data archives utilizing HTML. The JPG format is universal and enables hassle-free transfer of data. These data yield a pictoral view of the seismic data acquired. 20020904 20020916 Publication Date Complete None planned -111.5 -111.17 42.2 41.08 None seismic reflection SEG-Y Chirp JPEG JPG U.S. Geological Survey USGS Coastal and Marine Geology Program CMGP Woods Hole Field Center None Bear lake Utah Idaho Western Lakes North America United States None The U.S. Geological Survey must be referenced as the originator of the dataset in any future publications. Jane F. Denny U.S. Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543 USA 508-457-2311 508-457-2310 jdenny@usgs.gov Joint Photographic Experts Group (JPEG) Image format Processed seismic data were converted to JPG format for ease of file display. Quality control was conducted during processing. Complete WAAS (Wide Area Augmentation System) is assumed to be accurate within 1-2 meters. Standard GPS is assumed accurate within 5-10 meters. All WAAS data are referenced to WGS84. The data were acquired with an Edgetech 424 kHz CHIRP sub-bottom profiler. The system was towed at the surface, close to the survey vessel. Horizontal accuracy is thus assumed to be within +/-3 meters. Raw SEGY-Y data were processed utilizing Colorado School of Mines Seismic Unix (SU) seimsic processing software. The seismic data were recorded with TEI Delph Seismics acquisition software. Durinr processing, the SEG-Y data were converted to SU format. Gains were applied to the data to reduce noise and enhance the data. 'Mute' was used to remove all noise/signals within the water column. The data were then converted to postscript and JPG formats. 20020916 Jane F. Denny US Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543 USA 508-457-2311 508-457-2310 jdenny@usgs.gov Raster pixel Jane F. Denny US Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543 USA 508-457-2311 508-457-2310 jdenny@usgs.gov This publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials. 20020119 2002 Jane F. Denny US Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543 USA 508-457-2311 508-457-2310 jdenny@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 None None