### Conversion Factors
**International System of Units to U.S. customary units**
Multiply |
By |
To obtain |
Length |
centimeter (cm) |
0.3937 |
inch (in.) |
millimeter (m) |
0.03937 |
inch (in.) |
meter (m) |
3.281 |
foot (ft) |
kilometer (km) |
0.6214 |
mile (mi) |
kilometer (km) |
0.5400 |
mile, nautical (nmi) |
meter (m) |
1.094 |
yard (yd) |
Area |
square kilometer (km^{2}) |
0.3861 |
square mile (mi^{2}) |
Velocity |
meter per second (m/s) |
3.281 |
foot per second (ft/s) |
###
### Datum
Vertical coordinate information for bathymetry and seismic horizons are referenced to North American Vertical Datum of 1988 (NAVD 88).
Vertical coordinate information for seismic profiles and geologic cross sections are referenced to instantaneous sea level (converted from two-way traveltimes to meters by using a constant sound velocity of 1,500 meters per second through water and sediments).
Depth values cited from some references are given in meters below sea level (mbsl).
Elevation, as used in this report, refers to distance above or below the vertical datum.
Horizontal coordinate information is referenced to the World Geodetic System of 1984 (WGS 84) in a
Geographic Coordinate System.
###
### Supplemental Information
Particle size in phi units may be converted to millimeters (mm) as follows: mm=2^{-phi}.
The frequencies produced by marine acoustic instruments are measured in hertz (Hz), periods per second. |