Gideon Tibor - Academia.edu (original) (raw)

Papers by Gideon Tibor

Tectonophysics, Dec 1, 1997

... The succession has been divided into the Chiaramonte (TithonianHauterivian), Hybla (Hauterivi... more ... The succession has been divided into the Chiaramonte (TithonianHauterivian), Hybla (HauterivianAlbian) and ... R., D&#x27;Argenio, B. (Eds.), Guida alia geolo gia delia Sicilia occidentale. ... In: Max, MD, Colantoni, E (Eds.), Geological Development of the SicilianTunisian Platform. ...

Tectonophysics, 2006

A 3-D layered structure of the Levant and the southeastern Mediterranean lithospheric plates was ... more A 3-D layered structure of the Levant and the southeastern Mediterranean lithospheric plates was constructed using interpretations of seismic measurements and borehole data. Structural maps of three principal interfaces, elevation, top basement and the Moho, were constructed for the area studied. This area includes the African, Sinai and Arabian plates, the Herodotus and the Levant marine basins and the Nile sedimentary cone. In addition, an isopach map of the Pliocene sediments, as well as the contemporaneous amount of denuded rock units, was prepared to enable setting up the structural map of the base Pliocene sediment. Variable density distributions are suggested for the sedimentary succession in accord with its composition and compaction. The spatial density distribution in the crystalline crust was calculated by weighting the thicknesses of the lower mafic and the upper felsic crustal layers, with densities of 2.9 g/cm 3 and 2.77 g/cm 3 , respectively. Results of the local (Airy) isostatic modeling with compensation on the Moho interface show significant deviations from the local isostasy and require variable density distribution in the upper mantle. Moving the compensation level to the base of the lithosphere (∼ 100 km depth) and adopting density variations in the mantle lithosphere yielded isostatic compensation (± 200 m) over most of the area studied. The spatial pattern obtained of a density distribution with a range of ± 0.05 g/cm 3 is supported by a regional heat flux. Simulations of the flexure (Vening Meinesz) isostasy related to the Pliocene to Recent sedimentary loading and unloading revealed concentric oscillatory negative and positive anomalies mostly related to the Nile sedimentary cone. Such anomalies may explain the rapid subsidence in the Levant Basin and the arching in central Israel, northern Sinai and Egypt during Pliocene-Recent times. Comparison between the observed (Bouguer) gravity and the calculated gravity for the constructed 3-D lithospheric structure, which has variable density distributions, provided a good match and an independent constraint for the large-scale structure suggested and confirmed an oceanic nature for the Levant Basin lithosphere.

Frontiers in Earth Science, 2021

Diagnostic morphological features (e.g., rectilinear seafloor scarps) and lateral offsets of the ... more Diagnostic morphological features (e.g., rectilinear seafloor scarps) and lateral offsets of the Upper Quaternary deposits are used to infer active faults in offshore areas. Although they deform a significant seafloor region, the active faults are not necessarily capable of producing large earthquakes as they correspond to shallow structures formed in response to local stresses. We present a multiscale approach to reconstruct the structural pattern in offshore areas and distinguish between shallow, non-seismogenic, active faults, and deep blind faults, potentially associated with large seismic moment release. The approach is based on the interpretation of marine seismic reflection data and quantitative morphometric analysis of multibeam bathymetry, and tested on the Sant’Eufemia Gulf (southeastern Tyrrhenian Sea). Data highlights the occurrence of three major tectonic events since the Late Miocene. The first extensional or transtensional phase occurred during the Late Miocene. Since...

EGU General Assembly Conference Abstracts, Apr 1, 2017

Quarterly Journal of Engineering Geology and Hydrogeology, 2020

The cities of Aqaba, Jordan and Elat, Israel are vulnerable to seismic damage because they are bu... more The cities of Aqaba, Jordan and Elat, Israel are vulnerable to seismic damage because they are built over the active faults of the Dead Sea Transform that are the source of historically destructive earthquakes. A liquefaction susceptibility map was generated for the Aqaba–Elat region. Borehole data from 149 locations and the water table depth were used to calculate effective overburden stress in the Seed–Idriss simplified method. The liquefaction analysis was based on applying a cyclic loading scenario with horizontal peak ground acceleration of 0.3 gin a major earthquake. The liquefaction map, compiled using a GIS platform, shows high and moderate liquefaction susceptibility zones along the northern coast of the Gulf of Aqaba that extend 800 m inland from the shoreline. In Aqaba, several hotels, luxury apartment complexes, archaeological sites, ports and commercial districts are located within high and moderate liquefaction zones. In Elat, the seaport and the coastal hotel district...

The Gulf of Eilat/Aqaba is the northeast arm of the Red Sea and was formed with the initiation of... more The Gulf of Eilat/Aqaba is the northeast arm of the Red Sea and was formed with the initiation of the Red Sea rifting in the Late Oligocene to Early Miocene. The studied area at the northern part of the Gulf is the transition zone between en echelon basin (the Eilat Deep) to the adjacent continental sedimentary basin in the Arava Valley and might be the location where a transverse fault transfers the major part of the left lateral transform deformation from the east to the west. The cities of Aqaba and Eilatare are built directly over the active faults of the Dead Sea transform (DST) fault system and are most vulnerable to destructive damage from a devastating future tectonic activity. The aim of this ongoing research (2006-2012), supported by the USAID MERC program, is to evaluate the risks to these cities by conducting detail high resolution geophysical and geological studies of the Gulf Head and the adjacent land area. The present seminar will describe the complex tectonic settin...

Symposium on the Application of Geophysics to Engineering and Environmental Problems 2015, 2015

Modern multielectrode and multichannel resistivity systems have made it relatively easy and rapid... more Modern multielectrode and multichannel resistivity systems have made it relatively easy and rapid to collect time domain induced polarization (IP) data in near surface surveys. This paper will examine a wide variety of applications through case studies in a variety of geological settings in Western Canada. Case studies will show various applications and complementary features of IP surveys including distinguishing salt water from conductive clays, identifying faults, locating deeply buried structures underneath active facilities, and distinguishing landfilled debris from leachate. IP data sets will be correlated with other data sets including resistivity, seismic reflection, and borehole geophysical parameters.

Satellite-derived bathymetry provides a useful reconnaissance tool for hydrographic surveying off... more Satellite-derived bathymetry provides a useful reconnaissance tool for hydrographic surveying offices in planning and implementing a prioritized survey program. Specific uses of the satellite-derived bathymetry include characterization of coastal areas and monitoring seafloor changes that have occurred since the last hydrographic survey. To be useful for hydrographic surveying offices in developing nations, the procedures must be based on readily-available data and software. In keeping with standard hydrographic surveying practice, the derived bathymetry must also be accompanied by uncertainty estimates. Recently a procedure was developed for the use of publicly-available, multispectral satellite imagery to map and portray shallow-water bathymetry in a GIS environment. Landsat imagery and published algorithms were used to derive estimates of the bathymetry in shallow waters. The most appropriate algorithm to derive bathymetry was determined in the study based on performance using di...

Journal of Geophysical Research: Solid Earth, 2014

Ocean Remote Sensing and Applications, 2003

SISCAL (Satellite-based Information System on Coastal Areas and Lakes) is a pan-European project ... more SISCAL (Satellite-based Information System on Coastal Areas and Lakes) is a pan-European project dedicated to develop facilities to provide end-users with customized and easy-to-use data for environmental monitoring of coastal areas and lakes. The main task will be to create a software system providing Near-Real-Time information on the aquatic environment (using instruments such as AVHRR, MODIS or MERIS) and ancillary

Israel Journal of Earth Sciences, 2009

... Aharon (Ronnie) Sade,a Gideon Tibor,b John K. Hall,c,* Moti Diamant,d Hadar Sade,a Gal Hartma... more ... Aharon (Ronnie) Sade,a Gideon Tibor,b John K. Hall,c,* Moti Diamant,d Hadar Sade,a Gal Hartman,a,b Gideon Amit,b Boris Schulze ... The second survey (Ben-Avraham et al., 1990) was carried out in 1986 and 1987 along mutually perpendicular N–S and E–W lines with 100 m ...

Limnology and Oceanography, 2011

A set of satellite images of chlorophyll a concentration for Lake Kinneret (Israel) from the peri... more A set of satellite images of chlorophyll a concentration for Lake Kinneret (Israel) from the period February to April 2007 captured the temporal evolution of horizontal patchiness that developed during the typical spring bloom of the dinoflagellate Peridinium gatunense. Narrow bands of high concentration located adjacent to the shoreline at the start of the bloom were followed by progressive propagation of this high-concentration region from the shoreline toward the center of the lake as the bloom proceeded. A three-dimensional (3-D) hydrodynamic numerical model and an analytical model for a flat-bottomed elliptical basin together explain the observed phenomenon. The spatial structure of Kelvin waves, which were demonstrated to most likely be present in February and April due to resonance, produced regions of high velocity gradient, contributing to horizontal dispersion close to the shoreline. This region of high dispersion was narrow and close to the shoreline at the start of the bloom when the Burger number was relatively small, but it widened over the course of the season as the Burger number increased due to increasing stratification. In addition, an increase in the dispersion rate with time in the lake interior was inferred from numerical simulation due to increasing wind speeds and a thinner surface layer. Physical processes, in this case, horizontal dispersion as a result of both Kelvin waves and wind, can play an important role in governing the dynamics and spatial evolution of dinoflagellate blooms in lakes.

Journal of Geophysical Research: Solid Earth, 1993

Analyses and modeling of gravity data in the Dead Sea pull-apart basin reveal the geometry of the... more Analyses and modeling of gravity data in the Dead Sea pull-apart basin reveal the geometry of the basin and constrain models for its evolution. The basin is located within a valley which defines the Dead Sea transform plate boundary between Africa and Arabia. Three hundred kilometers of continuous marine gravity data, collected in a lake occupying the northern part of the basin, were integrated with land gravity data from Israel and Jordan to provide coverage to 30 km either side of the basin. Free-air and variable-density Bouguer anomaly maps, a horizontal first derivative map of the Bouguer anomaly, and gravity models of profiles across and along the basin were used with existing geological and geophysical information to infer the structure of the basin. The basin is a long (132 km), narrow (7-10 km), and deep (-<10 km) full graben which is bounded by subvertical faults along its long sides. The Bouguer anomaly along the axis of the basin decreases gradually from both the northern and southern ends, suggesting that the basin sags toward the center and is not bounded by faults at its narrow ends. The surface expression of the basin is wider at its center (<16 km) and covers the entire width of the transform valley due to the presence of shallower blocks that dip toward the basin. These blocks are interpreted to represent the widening of the basin by a passive collapse of the valley floor as the full graben deepened. The collapse was probably facilitated by movement along the normal faults that bound the transform valley. We present a model in which the geometry of the Dead Sea basin (i.e., full graben with relative along-axis symmetry) may be controlled by stretching of the entire (brittle and ductile) crust along its long axis. There is no evidence for the participation of the upper mantle in the deformation of the basin, and the Moho is not significantly elevated. The basin is probably close to being isostatically uncompensated, and thermal effects related to stretching are expected to be minimal. The amount of crustal stretching calculated from this model is 21 km and the stretching factor is 1.19. If the rate of crustal stretching is similar to the rate of relative plate motion (6 mm/yr), the basin should be-•3.5 m.y. old, in accord with geological evidence. ment discontinuities across en echelon faults in a brittleelastic medium [Rodgers, 1980; $egall and Pollard, 1980; Bilham and King, 1989]. The evolution of deep basins (deeper than 2-3 km) is expected to be more complicated as they result from either larger displacements along the fault system or from rotation of the axis of extension relative to the fault system. Furthermore, the deformation of deep 1U.S. Geological Survey,

Journal of Geophysical Research, 1992

The late Tertiary subsidence history of the southern Levant continental margin, situated in the s... more The late Tertiary subsidence history of the southern Levant continental margin, situated in the southeastern Mediterranean Sea, was quantitatively analyzed. Paleodepth reconstruction across the margin off Ashdod suggests the existence of a deep basin in pre-Messinian time which resembles the present one. This implies that. the deposition of the evaporites in the study area during the Messinian desiccation of the Mediterranean Sea occurred in a deep basin. The path of the tectonic subsidence of the basement since early Tertiary is generally smooth as expected from the nature of the thermal subsidence. The unconformity beneath the Messinian indicates erosion of 50-200 m at the coastal plain. In the Pliocene, the tectonic subsidence in the coastal plain and shelf area diverts from the expected thermal path and increases from 250 m to 450 m, respectively. In the Quaternary the rate of tectonic subsidence nearly resumed the predicted thermal subsidence. Sedimentation and subsidence rates decrease but are still higher than those of the pre-Messinian. We suggest that the evolution of the southern Levant margin is most probably influenced by three main causes: (1) the Messinian event in late Miocene, (2) the deposition of large volumes of Nile derived sediments since the Pliocene, and (3) the flexural response of the lithosphere to the load from the Nile delta and/or from the uplift of the Judea Mountains (the western shoulder of the Dead Sea Transform). We interpret the latter to be the cause of the anomalous subsidence of the southern Levant margin during the Pliocene. boundaries include the Dead Sea Transform to 1000 rn high). These mountains are the western the east, the Cyprian arc to the northwest, and shoulder of the Dead Sea Transform and are the Taurus mountains and Bitlis suture to the situated about 40 km east of the coast line. north. A change in the relative motion of At the end of Miocene the Messinian desic-Africa with respect to Eurasia in the Late cation of the Mediterranean Sea occurred. Cretaceous caused a compressional phase that led Although this event lasted less than 1 m.y., it to the development of a series of folded and led to a major erosional phase on the margins faulted structures known as the "Syrian arc ' of the Mediterranean and to deposition of thick layers of salt and evaporites in the basinal 1Now at Lamont-Doherty Geological Observatory, areas [Hsu et al., 1977]. Since the Pliocene, Palisades, New York. large volumes of clay and silt. have been 2Now at Petroleum Infrastructure Corp., Ltd., Tel Aviv, transported from the Nile delta and deposited Israel. on the continental margin.

… 2010, held 2-7 May …, 2010