Seafloor Heat Flow : Methods and Observations

8 Definitions 9 Heat flow. The rate of thermal energy transfer in a medium 10 driven either conductively along a thermal gradient or 11 advectively via mass transport. The standard unit is 12 watts, W. The term is also used to describe a subdiscipline 13 of geophysics, as in the title of this entry. 14 Conductive heat flux. The heat flow per unit area diffusing 15 by conduction along a thermal gradient, determined as the 16 product of the thermal gradient and thermal conductivity. 17 The standard unit is W m . The term heat flow density 18 has been used correctly as a synonym; the term heat flow, 19 traditionally but inexactly used as a synonym for heat flux, 20 more strictly applies to the integrated heat flux over 21 a specified area or region (watts). 22 Advective heat flux. The rate of heat transfer per unit area 23 carried by a moving medium, proportional to the velocity 24 and the heat capacity of the medium. The standard unit is 25 W m . 26 Thermal conductivity. The quantity that defines the ability 27 of a medium to transfer heat by steady-state diffusion. The 28 standard unit is W m 1 K . 29 Hydrothermal circulation. Large-scale pore-fluid convec30 tion driven by thermal buoyancy, in which fluid flux and 31 advective heat flux are strongly influenced by the perme32 ability structure of the host formation. 33 History of observations