122 • Marine Minerals: Exploring Our New Ocean Frontier 



USGS used GLORIA in 1984 to survey the EEZ 

 adjacent to California, Oregon, and Washington. 

 This entire area (250,000 square nautical mOes) was 

 surveyed in 96 survey days (averaging about 2,600 

 square nautical miles per day). In 1985, USGS used 

 GLORIA to complete the survey of the Gulf of 

 Mexico started in 1982 and to survey offshore areas 

 adjacent to Puerto Rico and the Virgin Islands. In 

 1986, GLORIA surveys were conducted in parts 

 of the Bering Sea and in Hawaiian waters. The ben- 

 efits of using GLORIA data to reconnoiter the EEZ 

 have become apparent in that, among other things, 

 several dozen previously unknown volcanoes (po- 

 tential sites for hard mineral deposits) were discov- 

 ered.' These and other features appear in USGS's 

 recently published west coast GLORIA adas, a col- 

 lection of 36, 2- by 2-degree sheets at a scale of 

 1:500,000.'° Digital GLORIA data will be even 

 more useful in the future, as additional bathymet- 

 ric, magnetic, gravity, and other types of data are 

 collected and integrated in the database. 



USGS has now acquired its own GLORIA (it 

 previously leased one owned by lOS). Known as 

 GLORIA Mark III, this newest system is an im- 

 proved version of earlier models, incorporating 

 titanium transducers and a digitized beam-steering 

 unit to correct for yaw." During the next several 

 years, GLORIA Mark III is scheduled to survey 

 Alaskan, Hawaiian, and Atlantic EEZs. The USGS 

 plan is to survey the entire U.S. EEZ by 1991, with 

 the exception of the U.S. Trust Territories, the ice- 

 covered areas of the Beaufort and Chukchi Seas, 

 and continental shelf areas (i.e., areas shallower 

 than 200 meters (656 feet)). 



The potential market for GLORIA surveys has 

 recently attracted a private sector entrepreneur, 

 Marconi Underwater Systems of the United King- 

 dom. Marconi is convinced that other coastal states 

 win wish to explore their EEZs and will look to com- 

 mercial contractors for assistance. Eventually, 

 USGS also may be in a position to use its GLORIA 

 for mapping the EEZs of other countries. Once the 

 U.S. EEZ is surveyed, GLORIA would be avail- 

 able for use to explore EEZs of countries that have 

 cooperative science programs with the United 

 States. 



USGS is coordinating its GLORIA program 

 with the detailed EEZ survey program of the Na- 

 tional Oceanic and Atmospheric Administration 

 (NOAA). NOAA is using Sea Beam and Bathy- 

 metric Swath Survey System (BS^) technology (dis- 

 cussed below) to produce detailed bathymetric 

 charts. NOAA uses GLORIA information pro- 

 vided by USGS for determining survey priorities. 

 USGS geologists use NOAA's bathymetry in con- 

 junction with GLORIA data to assist in interpret- 

 ing the geologic features of the seafloor. The most 

 accurate geological interpretations wLU result from 

 use of many different types of data simultaneously: 

 side-looking sonar, bathymetry, gravity, magnetic, 

 seismic, electrical, etc. 



Midrange Side-Looking Sonar 



Like GLORIA, midrange systems record the 

 acoustic reflection from the seafloor; however, they 

 are capable of much higher resolution. In addition, 

 whereas GLORIA is used to obtain a general pic- 

 ture of the seafloor, midrange and shortrange side- 

 looking sonars are usually used for more detailed 

 surveys. A seabed miner interested in looking for 

 a specific resource would select and tune the side- 

 looking sonar suitable for the job. For example, 

 manganese nodule fields between the Clarion and 

 Clipperton fracture zones in the Pacific Ocean were 

 mapped in 1978 using an imaging system specially 

 designed and built for that purpose. 



The Sea Mapping And Remote Characteriza- 

 tion systems — SeaMARC I and II — developed by 

 International Submarine Technology, Ltd. (1ST), 

 and, respectively, Lamont-Doherty Geological Ob- 

 servatory and the Hawaii Institute of Geophysics 

 (HIG), are two of several such systems available. 

 SeaMARC I recently has been used to survey the 

 Gorda and Juan de Fuca ridges.'^ It can resolve 

 tectonic and volcanic features with as little as 3 

 meters of relief.'^ Higher resolution is obtained be- 

 cause midrange systems use wider bandwidths and 

 generally operate at higher frequencies (10 to 80 



'Ibid. 



'"EEZ Scan 1984 Scientific Staff, Adas. 



"D. Swinbanks, "New GLORIA in Record Time," Nature, vol. 

 320, Apr. 17, 1986, p. 568. 



'y.G. Kosalos and D. Chayes, "A Portable System for Ocean Bot- 

 tom Imaging and Charting," Proceedings, Oceans 83, sponsored by 

 Marine'Technology and IEEE Ocean Engineering Society, Aug. 29- 

 Sept. 1, 1983, pp. 649-656. 



"E.S. Kappel and VV.B.F. Ryan, "Volcanic Episodicity and a Non- 

 Steady StatC'Rift Valley Along Northeast Pacific Spreading Centers: 

 Evidence from Sea Marc I," Journal of Geophysical Research, 1986, 

 in press. 



