John K. Hall

Continental breakup by a leaky transform: the gulf of elat (aqaba).

The floor of the Gulf of Elat consists of five distinct deeps. Its structure is controlled by faulting which has produced rhomb-shaped grabens. The gulf is a newly formed plate boundary between Arabia and Sinai.

Slice Tectonics in the Eastern Mediterranean Basin

Two systems of counterclockwise-converging and northeastward-curving left-lateral shears, which belong to a global pattern of spiraling geosutures, have played a major role in shaping the Eastern Mediterranean. The first one, the Pelusium system, composed of the Dead Sea, Pelusium Line, and Qattara-Eratosthenes shears, is primarily responsible for the structure of the eastern Levantine Basin and the Levant. The other one, composed of the Pliny-Sirte and the Antalia shears, forms the divide between the western Levantine and Ionian basins. Several other geosutures, such as the Coastal Fault of Israel, are also found within the Pelusium system, but they are not necessarily shears. Depositional basins were formed along the axes of the lithospheric subslices that are bound by the main shears. The troughs of these basins systematically hug their eastern boundary shears, whereas their basinal fill moderately rises and thins toward the west; excessive sediment accumulation has taken place in these troughs since Paleozoic or even late Precambrian time. The Levantine Basin, with its 15–16 km thick sedimentary sequence, is therefore considered a relict of the Tethys Ocean, which is of an appreciably older age than hitherto considered.

Distribution of Holocene sediments and neotectonics in the deep north basin of the Dead Sea

Abstract The distribution of Holocene sediments and active faults in the central portion of the northern Dead Sea basin was analyzed from high resolution seismic reflection data. The seismic reflection profiles reveal that sediments buried at a shallow depth are flat-lying, continuous, and unfaulted within the central basin floor. Four prominent subsurface seismic reflectors were identified that, based on limited core data, represent the contact between rock salt and marl layers. Isopach and structural maps of recent sediments indicate an asymmetry of active subsidence with thick accumulations located closer to the east margin of the basin. Sediment thickness increases within a rhomb-shaped depression whose long-axis is oriented approximately 20°–30° counterclockwise to the regional basin-bounding faults. The morphology and trend of the locus of maximum subsidence suggests tectonic control of the depression. However, the proximity of the depocenter of recent sediments to the Ein Gedi diapir and rim depression suggests that local sub-basinal subsidence may also be related to movement of rock salt at depth. The basinal strata are deformed along the faults that form a bathymetric escarpment along the west, east, and south margins of the north basin of the Dead Sea. Thinning of recent sediments toward the faults indicates syntectonic deposition.

Spatially-resolved uplift rate of the Mount Sedom (Dead Sea) salt diapir from InSAR observations

Pe’eri, S., Zebker, H.A., Ben-Avraham, Z., Frumkin, A., and Hall, J.K. 2004. Spatially-resolved uplift rate of the Mount Sedom (Dead Sea) salt diapir from InSAR observations. Israel J. Earth Sci. 53: 99‐106. Mt. Sedom, a diapiric “salt wall” southwest of the Dead Sea, was formed by extrusion of salt layers through passages in overlying sediments. Here we present the spatiallyresolved uplift rate of the salt body diapir derived from spaceborne Interferometric Synthetic Aperture Radar (InSAR) observations. Although the average uplift rate has been estimated, spatially resolved uplift was not available due to the paucity of uplift observations. We processed 13 interferograms (InSAR deformation images) spanning time periods ranging from 421 to 1949 days, and calculated the spatial distribution of uplift rate for the two blocks that make up Mt. Sedom. We found average uplift rates of 8.27 ± 0.28 mm/yr and 6.88 ± 0.31 mm/yr for the northern and the southern blocks, respectively. These results represent relatively high values when compared to others measured in salt diapirs around the world (excluding certain domes in Iran). The tectonic processes in the area may influence these relatively high values, and the division of the diapir into two blocks.

Lake Bathymetry and Bottom Morphology

The bathymetry and morphology of Lake Kinneret is influenced by its complex tectonic structure and by high annual sedimentation (~ 100,000 t year−1 for the past 50 years). In general, the lake floor has an asymmetric shape with mild bathymetry at its western part and steep bathymetry at the eastern part. Based on a new multibeam bathymetric mapping conducted in 2008, the total surface area of the lake is 168.7 km2 (at water level − 209 m a.m.s.l.) with a maximum depth of 41.7 m (− 253.7 m). The water storage capacity ranges from 4,325 to 3,661 × 106 m3 at water levels of − 209 to − 214 m, respectively. A comparison of the 2008 multibeam bathymetry to echosounder bathymetry of 1986/1987 revealed dramatic changes in the lake bathymetry. The southern basin became significantly shallower; sediment accumulation over the 21 years between the two surveys may have accounted for up to 2 m rise in the lake floor at some places, estimated to represent ~ 10 × 106 t of sediment. The northern basin however does not show evidence for massive sedimentation (< 0.5 m), whereas judging by the − 214 m (a.m.s.l.) contour, the littoral perimeter had been eroded significantly. The existence of bathymetric lineaments on the lake floor indicates recent and active processes in the lake. Two main lineament trends were found: a N–S trend, mainly on the eastern and southwestern borders of the lake, probably associated with active traces of the Dead Sea fault system and a NW–SE trend, which is probably the continuation of the normal faults of the eastern Galilee fault system. The major morpholineament found in the 2008 bathymetry is located in the northwestern deeper parts of the lake (− 232 to − 242 m) and is N–S oriented. The epicenters of the October 2013 earthquakes are found in the vicinity of this lineament.