The capability of Landsat to detect some oil slicks in marine waters has been verified. Reflectance anomalies associated with the slicks have been detected visually on film data, by photo-optical enhancement techniques and by computer processing. Applications of Landsat oil slick data include environmental monitoring of coastal waters and detection of natural seeps such as in the Santa Barbara Channel, which may serve as a worldwide exploration aid.
In recognition of the potential benefits of an oil detection capability by Earth resources satellites, the National Environmental Satellite Service of NOAA and the Earth Resources Observations System (EROS) Program Office of the U. S. Geological Survey, both independently and in collaboration with NASA, engaged in studies of oil slick detection from Landsat-l and -2 data. A demonstrated capability to detect oil floating on inland and coastal waters could result in two potentially important applications:
Environmental - to detect and delineate oil spills, and thus be used to guide cleanup operations.
Exploration - to detect floating oil that originated from onshore or submarine seeps, indicative of a source reservoir of petroleum.
Since the launch of the first Earth Resources Technology Satellite (since renamed."Landsat-l") in July 1972, a number of Earth scientists have observed apparent oil slicks on coastal and inland waters in widespread locations around the world. Deutsch, Strong, and Rabchevskyl reported on these observations, and listed them by scene number along with literature citations. In all cases, these apparent oil slicks were interpreted by the investigators to have originated from man-made sources including accidental spills, broken pipelines, and discharges from ships. From the results of the various studies on Landsat-l and Landsat-2's oil detection capability, it can be concluded that Landsat or future Earth-resources satellites employing the same or refined sensor arrays under operational conditions can be used for environmental applications. These include, obviously, locating manoriginated spills, guiding any attempted cleanup operations, and determining or suggesting the source or mode of origin. Operational remote sensing for these applications would require repetitive coverage-hopefully at increased frequency--and real time or near real time data collection, processing, and dissemination capabilities.
In order to determine the applicability of Landsat data to be used for exploration purposes, an experiment was conducted by Estes, Deutsch, and Muchow2 to determine whether the known natural oil seep at Coal Oil Point in the Santa Barbara Channel had been detected at any time by Landsat. A Landsat capability to detect relatively small subtle natural oil seeps (compared with a point-source major oil spill) would be highly significant for two reasons:
A verified detection capability would represent a potential application for coastal-zone petroleum exploration.
Archival Landsat data might contain valuable information for exploration. Halbouty3 observed that "Landsat imagery may make possible the identification of natural marine oil seeps with consequent improvement in the efficiency of offshore oil exploration."
