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USGS Coastal and Marine Field Data Catalog for Monterey Bay National Marine Sanctuary and central California watersheds (opens in a new window)

Field Data Catalog - Monterey Bay National Marine Sanctuary   (opens in a new window)
Main directory page for USGS Coastal and Marine Data for the Monterey Bay National Marine Sanctuary.

• Bathymetry   (opens in a new window)
  Bathymetry is water depth relative to sea level. Depths are almost always derived indirectly by measuring the time required for a signal to travel from a transmitter, to the bottom, and back to a receiver. This travel time is then converted to a depth based on a variety of estimations of the signal speed through the water column. A time key is associated with each record for correlation with other information datasets.

• Gravity   (opens in a new window)
  Gravity is a measure of the attraction exerted by the Earth on a mass. The initial "uncorrected" gravity measurement is corrected for meter drifting and for Eotvos effects to produce an "observed" gravity measurement. A time key is associated with each record for correlation with other information datasets.

• Magnetics   (opens in a new window)
  Magnetics refers to the magnetic field of a body of rock. Local differences from the surrounding rocks are usually the primary concern. These anomalies when used with other geophysical information (such as gravity) indicate different types of rocks and magnetic reversals. A time key is associated with each record for correlation with other information datasets.

• Navigation   (opens in a new window)
  Navigation records the position of a data-collection platform at a specific time. The position is commonly a latitude/longitude pair. A time key is associated with each record for correlation with other information datasets.

• Samples   (opens in a new window)
  Samples are obtained using a variety of types of cores, dredges, traps, nets, grabs, and bottles. A time key is associated with each record for correlation with other information datasets.

• Seismic   (opens in a new window)
  Seismic covers a wide range of information including: conventional multichannel, high-resolution multichannel, conventional single channel, high-resolution single channel, very high resolution single channel, and wide angle reflection/refraction. Seismic data are collected by shooting a source at either: a regular time interval, or a regular distance interval. Each "shot" is an actual sound burst in the water. These systems use devices such as: airguns, waterguns, sparkers, sonar, and sonobuoys to produce signal pulses. A time key is associated with each record for correlation with other information datasets.