an increasing emphasis on cooperative and multidisciplinary studies. John Wesley Powell, the Survey's second Director (1881-94), extended shared programs originated by Director King to include cooperative mapping projects with several States. Powell called geology the most comprehensive of all sciences, though he held that its most fundamental connection was with topography. He authorized independent topographic mapping within the Geological Survey as a basis for the geological map of the United States authorized by Congress in 1882. Although Powell directed the Survey's geological work largely toward the preparation of the national geologic map by way of the geologic folios project, topographic mapping remained the largest single element in the Survey's program during his administration. During the 1880's, Powell arranged cooperative mapping projects with the surveys of several northeastern States; work was continued and was expanded by subsequent Directors. In 1902 and 1903, as an example, Director Walcott authorized a cooperative investigation by Geological Survey and Kentucky earth scientists of the areal and economic geology of the western Kentucky portion of the IllinoisKentucky lead-zinc district. This por

tion of the Survey's tradition of cooperative studies culminated in the recently completed project (1960-78) by the U.S. and Kentucky Geological Surveys that mapped geologically all of the State's 7.5-minute quadrangles using topographic maps completed in the previous decade. The results of that work have already doubled the State's inventory of mineral commodities and advanced its investigations of engineering and environmental geology and planning for effective use of its land.

Some of the Geological Survey's earliest investigations involved the application of expertise in several scientific disciplines. Today, the Survey continues to participate in many cooperative multidisciplinary programs with local, State, and Federal agencies. In fact, the Survey has agreements for cooperative work with all of the States, numerous local and regional municipal government organizations, and many Federal agencies. The Survey derives a significant portion of its operating funds from these organizations for work in their behalf. Among the most visible of these investigations are the Survey's contributions to the scientific exploration of space, directed primarily by the National Aeronautics and Space Administration, by map

ping the Moon and other astronomical bodies, training astronauts in the earth sciences, conducting investigations with data from Earth-orbiting satellites, and contributing to interplanetary studies by unmanned probes. Since World War II, the Geological Survey has also cooperated with the developing countries in assessing their mineral and energy resources. The advent of worldwide data from satellites enabled the Survey to join the cooperative global monitoring of seismic events and the mitigation of natural disasters and to conduct special studies based on satellite technology as well as technology transfer and training.

THE SURVEY'S
EXPANDED
RESPONSIBILITIES

After giving the Geological Survey authority to expand its operations nationwide in 1882, Congress subsequently assigned responsibilities to the Survey for evaluating the Nation's water resources, classifying and mapping its forest reserves, conducting subdivision and boundary surveys, classifying the public lands, supervising the exploration for and development of mineral and energy resources under Federal lease both on land and on the Outer Continental Shelf, and surveying U.S. possessions abroad. Between 1907 and 1934, the Geological Survey transferred some of these functions to newly established bureaus-Reclamation, Mines, Forest Service, and Grazing Service (now part of the Bureau of Land Management). In the years following World War II, the Geological Survey's commitment to research broadened and deepened as the Agency's investigations occupied new dimensions-polar regions, the sea floor, and space. In 1962, Congress authorized formal investigations by the Survey in areas outside the national domain. Since then, planetary studies, the use of Landsat imagery in mapping and geologic investigations, and added responsibilities for earthquake prediction, the reduction of the effects of earthquakes and other geologic hazards, and problems related to siting nuclear reactors and the disposal of hazardous wastes have provided even wider and newer fields to challenge the scientific spirit of the Survey.

1979-THE

CHALLENGES AHEAD

As it begins its second century of public service, the Geological Survey faces many of the same critical and difficult challenges that beset the Nation and the world at large. Solutions to problems that relate to the adequacy of future supplies of energy, minerals, and water resources; the wise and efficient use of our land; the reduction of damage to life and property from geologically related natural disasters; and the preservation of environmental quality require extensive knowledge of the Earth and its natural resources. The acquisition and dissemination of such knowledge to the persons responsible for the formulation and execution of governmental policies in the United States and to the general public remain basic responsibilities of the Survey. The challenges to the Survey in meeting these responsibilities increase as the Nation's growing population with its expanding needs press the limits of our finite land, resource base, and delicately balanced ecosystem. In many areas, the

knowledge and tools at hand are insufficient for these tasks and must be refined and expanded to make it possible to find and appraise mineral deposits that have no surface indications of their existence; to predict the location, time, and magnitude of earthquakes; or to define geologically safe environments for the disposal of hazardous wastes.

In view of the rising costs of its operations and the growing public pressure for immediate solutions to problems, the Survey must increase the efficiency and cost effectiveness of its operations. These requirements pose challenges to develop and to adapt sophisticated technology to the acquisition and analysis of data, including the storage, analysis, and display of data by computer; the use of remote sensing; digitization of map information; and the automation of water-data collection. Another challenge to the Survey, and to other scientific and technical organizations as well, is to improve its communications with the users of its informa

tion, not only to provide data and analyses rapidly, but to supply them in forms that are readily understandable and usable.

No less challenging are the problems involved in the Survey's regulatory responsibilities as mineral leasing and associated exploration, development, and production activities on the public land expand to new environments, such as the deeper waters of the Outer Continental Shelf, and to areas where mining can significantly affect the ecosystem if it is allowed to proceed without regard to land reclamation and the protection of other natural resources.

Fortunately, the Survey's first century of operations generated experience and traditions that will help it meet the challenges ahead, not only those characteristics already named, but also legacies of excellence and objectivity in its work, flexibility in its approach, and a readiness to respond to increasing public needs for sound information about the Nation's natural resources and physical environment.

The decade of the 1970's was marked by a sharply increased dependence by the United States on foreign energy sources, particularly crude oil. Although this dependence has been growing for the last 20 years, it was made clearly visible to the American public by the Arab oil embargo of 1973. In the years since 1973, petroleum prices have continually risen, but, in 1979, a reduction in the availability of foreign oil supplies, caused principally by the civil revolution in Iran, accelerated the increase in the world price of crude oil and again underscored the need for the United States to reduce its dependence on foreign energy supplies.

Many petroleum geoscientists believe that significant quantities of conventional oil and gas may be developed offshore on the continental shelves, slopes, and rises surrounding the United States. Large offshore sedimen

WASHINGTONOREGON

tary basins are known to exist adjacent to both the conterminous 48 States and the State of Alaska. The location of these potential exploration areas are shown in figure 1.

Although the United States long ago began to produce oil and gas from offshore areas, major exploration efforts prior to 1973 focused on the southern California coast, the western Gulf of Mexico, and the Upper Cook Inlet of Alaska. Exploration in some frontier (essentially unexplored) offshore U.S. basins did not move forward because of technological and operational problems associated with the exploration, drilling, and development of oil and gas, especially in the Arctic regions. Other offshore basins were considered to be poor places in which to explore because their potential for major petroleum discoveries was considered to be too small.

Figure 1.-The 17 frontier Outer Continental Shelf areas (excluding the Gulf of Mexico) of the United States. (From Edgar and Bayer, 1979.)

After the 1973 embargo, Government and industry refocused attention on the frontier offshore areas because resource specialists believed that the potential for finding large accumulations was better offshore than onshore. They believed that the long history of exploration, especially in the lower 48 States, had found most of the major onshore oil fields. Furthermore, the technology in drilling and development of offshore fields was improving, making exploration and development possible or potentially feasible in previously inaccessible areas and especially in deep water.

ESTIMATED POTENTIAL FOR OFFSHORE OIL AND GAS DEVELOPMENT

Estimates of the offshore undiscovered recoverable resources for oil and gas were published by the U.S. Geological Survey in Circular 725 (Miller and others, 1975). These estimates of the undiscovered producible oil and gas indicated that all of the U.S. offshore basin areas to 600 feet of water depth might contain, based on a low estimate at a 95-percent probability of occurrence, at least 10 billion barrels of oil and, based on a high estimate at a 5-percent probability of occurrence, at least 49 billion barrels of oil. Comparison of even the high resource estimate to all the domestic oil and gas which had been previously discovered, both onshore and offshore of approximately 145 billion barrels, indicated that this was not the large supply of oil which would completely solve our energy problems and eliminate our dependence on foreign sources. However, in comparison to our 1978 proven oil reserves of 28 billion barrels (American Petroleum Institute and others, 1979), offshore discoveries might make a significant contribution to our future energy supplies, especially if major accumulation could be found and developed quickly.

Offshore undiscovered recoverable gas resources were also estimated in Circular 725. It was estimated that all offshore basins to a water depth of 600 feet might contain, based on a low estimate at a 95-percent probability of occurrence, at least 42 trillion cubic feet of gas, and, based on a high estimate at a 5-percent probability of occurrence, at least 181 trillion cubic feet of gas. In terms of heating value, these gas estimates are approximately the equivalent of 7 billion to 30 billion barrels of oil. Taken together, the undiscovered recoverable oil- and gas-resource estimates indicate that there are significant targets for future offshore exploration. Large new offshore fields, if they could be discovered and developed quickly, would have significant impact on our near-term oil and gas supply problem because, in general, large fields have high rates of production in the years immediately subsequent to discovery and development. Additionally, estimated volumes of recoverable oil and gas resources offshore could increase in magnitude as technological advancements are made which make exploration and development in deeper waters or in hostile arctic environments feasible and as increased

world crude oil prices allow exploration to proceed into areas of high cost, high risk, or low potential. Thus, one of the Survey's most important functions is to inform the Government to the best of its collective abilities about the future oil and gas resources that are likely to be discovered offshore. Therefore, in the process of assessing frontier areas, the Survey aggressively supports the search for future oil and gas resources and collects data from areas that may not be considered as exploration targets today but are possible exploration targets tomorrow. In this regard the Survey's programs support the development of appraisal methodologies and the appraisal of the Nation's offshore oil and gas resources. Petroleum-related geologic studies play a vital role in this program. These studies have as a common objective the gathering and analysis of geologic, geophysical, and geochemical data to develop information and concepts concerning petroleum occurrence and genesis needed to support the Survey's resource-appraisal efforts.

Throughout the entire history of oil and gas development, there has been serious disagreement among qualified resource experts about how much oil and gas remains to be discovered and which forecasting techniques give the most reliable estimates. In recent years, estimates of oil and gas resources for the Nation as a whole seem to be converging; however, there is still considerable controversy about how much oil and gas remains to be discovered and especially in which offshore areas it will be found. Although some of these differences of opinion can be explained on the basis of data input and the methods and assumptions used in making the appraisals, many cannot. There is honest disagreement about the magnitude of our undiscovered oil and gas resources.

Because of these disagreements and because of the significance of the numbers, resource appraisal must be a continuing effort. New data must be gathered and new appraisal techniques must be developed to improve our ability to estimate undiscovered recoverable resources and to update previous estimates. The methods employed by geoscientists to estimate recoverable undiscovered resources in frontier offshore basins are based, in general, on analogs from other basins or areas which have been heavily explored. The knowledge and concepts developed about the occurrence and distribution of hydrocarbons in these analog areas are then applied in a variety of ways to frontier areas. The reliability of resource estimates in frontier areas depends in large measure on the prediction of the modes of occurrence for petroleum in the area and the selection of appropriate analogs to be used in making resource assessments on the basis of geologic knowledge. The whole process is iterative; as new data are collected by the Survey in the area of interest, new concepts about hydrocarbon occurrence are developed, and new analogs must be selected and applied. In general terms, the better our knowledge of the modes of occurrence and the better our understanding of the geologic factors that control how rich the known petroleum producing areas are, the better our ability to assess the magnitude of undiscovered resources in frontier or developing regions.

SURVEY ORGANIZATIONAL RESPONSIBILITIES FOR RESOURCE APPRAISAL

One of the objectives of this article is to explain the responsibilities of the Survey for appraising and evaluating the undiscovered recoverable oil and gas resources of the U.S. offshore areas as related to the offshore leasing process and also to explain how different units within the organization interact cooperatively to produce estimates of the quantities of oil and gas that may be discovered in the future.

The Survey essentially produces two types of resource appraisals or evaluations which contribute to the Department of the Interior's offshore leasing programs. Regional or basin resource appraisals based on broad geologic studies are produced to help determine the Federal offshore 5-year leasing schedules as well as to input regional geologic understanding into the early phases of a lease sale. Although there are other factors involved, regional oil and gas appraisals help the Department of the Interior prioritize where and when a lease sale will be held. The Survey also produces detailed tract appraisals and resource economic evaluations. The tract evaluations, which are the result of detailed geologic engineering and economic studies, are used by the Department of the Interior to determine the lowest acceptable bid for leasing particular tracts to industry in a lease sale in the Federal offshore leasing program. Both kinds of appraisals, regional and tract, require understanding of the petroleum geology of the basin as well as detailed knowledge of the geology of smaller areas within the basins.

These resource evaluations and appraisals are the responsibility of the Survey's Geologic Division and Conservation Division. The Conservation Division has the responsibility for making the detailed tract evaluations, and the Geologic Division has the responsibility for assessing entire basin areas. Figure 2 shows the

organizational structure within the Survey and the various units within each of the Divisions which carry out the underlying geologic studies and produce the needed appraisals and evaluations.

The individual organizations shown in figure 2 are quite similar in title, although some of these unit functions may vary considerably between Divisions in the details of their work. This similarity in structure results because resource-appraisal and resource-evaluation programs require the following essential kinds of activities: • Regional activities designed to collect basic geologic data and to carry out studies needed to support petroleum appraisals at both the basin and the tract level.

• Topical studies designed to develop new understanding about the geologic factors that control the generation and accumulation of oil and gas and the economics of oil and gas exploration and production.

• Assessment methodology studies that develop techniques for the application of petroleum data to the resource-appraisal process and statistical methods to manage and to produce the desired output.

As shown in the figure, there is an important overlap in both Divisions between the regional and topical activities and the resource-appraisal and evaluation activities. Important interactions also occur between Divisions that help to integrate the results of regional geologic and topical studies done for basin appraisals which are principally carried out in the Geologic Division and the detailed geologic engineering and economic studies done for tract evaluation which are carried out in the Conservation Division.