| Description | Spatial | Attributes |
Surface effects maps were produced for 530 of 747 underground nuclear detonations and one high-energy TNT detonation conducted at the Yucca Flat testing area of the Nevada Test Site between November 29, 1951 (Uncle detonation, Area 10) and September 23, 1992 (Divider detonation, Area 3). The Yucca Flat Surface Effects Map Database contains digital reproductions of these original maps. The database is provided in both ArcGIS (v. 8.2) geodatabase format and ArcView (v. 3.2) shapefile format. The earliest surface effects maps showed only the simple outlines of collapse sinks (or craters). Examples of these include Uncle (Operation Jangle, 1951) and Ess (Operation Teapot, 1955) in Area 10; and Fisher (U-3ah; 1961), Ringtail (U-3ak; 1961), and Stoat (U-3ap; 1962) in Area 3. The first detailed surface effects map was produced for the Stillwater (U-9c; 1962) detonation in Area 9. This map not only showed the location of the sink, but also the intricate pattern of surface cracks that were produced by the detonation in the vicinity of the Yucca Fault Zone. During the next thirty years, many complex surface effects maps were produced. This database contains the surface effects maps for 748 detonations. The combined (cumulative) length of surface effects in the database is 2,398 km (1,490 mi). In GIS digital format, the user can view all surface effects maps simultaneously, select and view the surface effects of one or more sites of interest, or view specific surface effects by area or site. Three map layers make up the database. They are: (1) the surface effects maps layer (yfse_n27f), (2) the bar symbols layer (yfse_bar_n27f), and (3) the ball symbols layer (yfse_ball_n27f). Additionally, an annotation layer, named "Ball_and_Bar_Labels," is contained in the geodatabase version of the database. This annotation layer automatically labels 580 of the 867 ball-and-bar symbols shown on these maps.
Post-detonation surface effects maps were produced for detonation sites using field and aerial-photo mapping techniques. The fractures produced by the detonations were mapped and reported on in many USGS Technical Letter reports. Features mapped included surface cracks (and fractures), collapse sinks, various types of fault movements, pressure ridges, and reactivated cracks. A final surface effects map, or "crack map" as they were often called, was prepared on stable-base mylar drafting film for use in USGS publications and reports. Ultimately, these maps were stored by the USGS in map files at the Denver Federal Center, Lakewood, Colorado. The digital reproduction and archiving of these maps was implemented as a means to not only store the original crack maps in a more permanent compact disc format, but to also make them accessible for scientific study and management activities.
1: This metadata file pertains to the three primary map layers that make up the database, as well as to all other area-wide and site-specific surface effects maps of the Yucca Flat testing area. 2: The three map layers are named as follows: yfse_n27f: polyline coverage containing the surface effects map features yfse_bar_n27f: polyline coverage containing the bars of the bar-and-ball symbols yfse_ball_n27f: point coverage containing the balls of the bar-and-ball symbols 3: The bar-and-ball symbols are used to illustrate vertical displacement on the down-thrown side of faults and vertically displaced cracks. The ball symbols (point coverage) contain an attribute field named OFFSET_CM. This field contains a numerical value that is used to label the fault symbols. The value indicates the amount of vertical offset (in centimeters) that was originally measured for these features.