A new reduction algorithm for marine heat flow measurements

Abstract

Multiple penetration heat flow surveys that employ “violin bow” multithermistor array instruments generate large quantities of high‐quality data. To cope with the problems associated with the reduction of these data, an algorithm has been developed which can be used to reduce the data automatically on a microcomputer. The algorithm is designed for use with a pulsed line source method of conductivity measurement, although it could be modified easily for use with the continuous line source method. The multiply iterative algorithm deals, on a sensor by sensor basis, with errors associated with nonideal probe construction and sediment entry, factors that affect the determination of both in situ temperatures and thermal conductivities. Numerical tests of the algorithm show that it is accurate and stable and fast enough for post‐real‐time reduction of data at sea. Practical tests on high‐quality data from the western Pacific show that accuracies are limited by the instrumental resolution; in these cases, the reduction algorithm provided determinations of undisturbed in situ temperatures to better than 1 mK and of in situ conductivities to within 1%.

Indications for the Occurrence of Gas Hydrates in the Fram Strait from Heat Flow and Multichannel Seismic Reflection Data

“…Processing of the heat flow measurements was carried out using an improved version of the HFRED software [25] assuming an asymptotic solution for the temperature decay function. A fixed conductivity of 1 W/mK was used, which is a rough mean of measured thermal conductivities from the North Atlantic and Arctic Ocean [20,26].…”

Explanatory Notes

“…The thermal response at the penetration of the WSTP is similar to that of the APC, but the reduction of the data is simpler because of its geometrical configuration. In fact, the data can be processed in a way similar to those of the modern marine heat flow probe (Villinger and Davis, 1987;Nagihara and Lister, 1993).…”

Heat flow and tectonics of the Ligurian Sea basin and margins

“…The most valuable application of the optimization routine is realized in an almost real-time automated heat flow data reduction system (e.g., Villinger and Davis, 1987).…”

“…Recently, Villinger andDavis (1987) andFang -385-et al (1987) have implemented minimization routines for finding optimal origin times, thus setting the stage for automated heat flow data reduction.…”

“…Therefore, the pulse-heating method essentially consists of noting at least one temperature at a known time after the pulse, performing a correction to achieve an asymptotic-equivalent temperature (see Lister, 1979;Hyndman et al, 1979;Villinger and Davis, 1987), and calculating K with Equation A3.9.…”