Illinois State Geological Survey Circular 578 69 Chapter 13: U.S. Geological Survey: A Synopsis of Three-dimensional Modeling Linda J. Jacobsen 1 , Pierre D. Glynn 1 , Geoff A. Phelps 2 , Randall C. Orndorff 1 , Gerald W. Bawden 2 , and V.J.S. Grauch 3 U.S. Geological Survey: 1 Virginia, 2 California, 3 Colorado Mission and Organizational Needs The U.S. Geological Survey (USGS) is a multidisciplinary agency that pro- vides assessments of natural resources (geological, hydrological, biological), the disturbances that affect those resources, and the disturbances that affect the built environment, natural landscapes, and human society. Until now, USGS map products have been generated and distributed primarily as 2-D maps, occasionally providing cross sections or overlays, but rarely allowing the ability to characterize and under- stand 3-D systems, how they change over time (4-D), and how they inter- act. And yet, technological advances in monitoring natural resources and the environment, the ever-increasing diversity of information needed for holistic assessments, and the intrinsic 3-D/4-D nature of the information obtained increases our need to gener- ate, verify, analyze, interpret, confirm, store, and distribute its scientific infor- mation and products using 3-D/4-D visualization, analysis, modeling tools, and information frameworks. Today, USGS scientists use 3-D/4-D tools to (1) visualize and interpret geo- logical information, (2) verify the data, and (3) verify their interpretations and models. 3-D/4-D visualization can be a powerful quality control tool in the analysis of large, multidimensional data sets. USGS scientists use 3-D/4-D technology for 3-D surface (i.e., 2.5-D) visualization as well as for 3-D volu- metric analyses. Examples of geological mapping in 3-D include characteriza- tion of the subsurface for resource assessments, such as aquifer character- ization in the central United States, and for input into process models, such as seismic hazards in the western United States. The USGS seeks to expand its 3-D/4-D capabilities in monitoring, interpret- ing, and distributing natural resource information, both by adopting and/ or developing new 3-D/4-D tools and frameworks and by promoting and enabling greater use of available tech- nology. Everything that shapes the Earth or affects its functions does so in 3-D space: water flowing over rocks, through aquifers, or as ice in glaciers; plants growing up into the atmosphere and down into the soil; the move- ment of animal life and pathogens within ecosystems; the movement of tectonic plates driven by deep con- vection beneath the crust; volcanic eruptions, floods, debris flows, and fires; the extraction, sequestration or migration of carbon, nutrients, con- taminants, biota, minerals, energy, and other resources. Until recently, the computational and visualization power necessary to understand these complex systems was limited to a handful of supercomputing centers or industrious scientists. This situation has now changed: personal computers equipped with fast video cards and vast storage allow wide access to 3-D/4-D tools and visualization. Business Model The annual USGS budget is approxi- mately US$1 billion from federal appropriations. The bureau also receives about US$500 million from outside entities such as other federal agencies, foreign governments, inter- national agencies, U.S. states, and local government sources. More than half of the outside funding supports collab- orative work in water resources across the country, and the balance of the funding supports work in the geologi- cal, biological, and geographic sciences and information delivery. The USGS has a workforce of approxi- mately 9,000 distributed in three large centers (Reston, Virginia; Denver, Colorado; Menlo Park, California) and in numerous smaller science centers across the 50 states. Scientific work is organized into “projects” run by principal investigators (PIs) who have significant latitude in planning and conducting research, including acqui- sition of the resources (e.g., equipment, computers, software) needed to carry out their studies. Due to the distributed nature of management and personnel and due to the independence of the PIs, finding common organizational solutions is often a challenge. For example, concerns regarding optimal use of 3-D/4-D technology within the USGS include these: s -ANYTOOLSANDSOLUTIONSAREEXPEN- sive. s 4HEUSERCOMMUNITYISNOTWELL coordinated and sometimes does not buy or share software licenses as a group. Buying power is not cur- rently maximized. s 0OCKETSOFSPECIALISTSAREEMERGING but there are few forums for sharing ideas and expertise. s 3TAYINGABREASTOFRAPIDLYEVOLVING technologies is difficult. Geological Setting The United States has a large variety of geological terranes that record more than 2 billion years of geological his- tory (Figure 13-1). The complexity of U.S. geology ranges from horizontal stacking of sediments in the Great Plains, Colorado Plateau, and Coastal Plain Physiographic Provinces to over- printing of compressional, extensional, and transform tectonics of the Pacific Border Province of the western United States (Figure 13-1). These varied geo- logical terranes present a challenge to