Four long seismic refraction profiles were shot in the Jordon‐Dead Sea‐Gulf of Elat graben and adjacent areas. From the arrival times of the Pg, Pn, and PmP phases, models of the crust and upper mantle were computed. The models show a crustal thickness of 30 km along the graben with a considerable thinning to the south along the Gulf of Elat. Between the Dead Sea, Red Sea, and the Mediterranean, the crust thickens, reaching a maximum thickness of 40 km west of the graben; but toward the Mediterranean, the crust thins rapidly to a thickness of 20 km while the overlying sediments thicken considerably. The results indicate an upper mantle upwelling in the graben area, connected to the Red Sea spreading mechanism, and the presence of a thin, possibly oceanic crust covered by a thick wedge of Mesozoic and Tertiary sediments underneath the Northern Negev of Israel and probably extending offshore to the Eastern Mediterranean.

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The planning, execution and preliminary results of a major Anglo-German explosion seismic project are presented in this, paper I of a series. This Lithospheric Seismic Profile in Britain (LISPB) was planned as a reversed 1000 km line between two major sea-shot points off Cape Wrath in Scotland and one in the English Channel; additional sea-shots and intermediate land-shots were fired to give reversed and overlapping crustal coverage (to 180400 km distance) along the line. In all, 29 shots were fired and 60 mobile magnetic tape stations recorded three-components of ground 'motion. The resulting 14 crustal and three long-range profiles have observations at intervals of typically 2-4 km. Recordings have been digitized and four examples of filtered, computer-plotted record sections are presented to illustrate data quality. In a preliminary analysis, phase correlations are discussed and some models presented; the latter especially are more relevant to future interpretations than to geological or tectonic problems. However, significant variations in crustal thickness and in the nature of the crust-mantle transition do seem to occur beneath the British Isles.

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