http://blogs.najah.edu/author/radwan-el-kelani An-Najah Blogs :: Radwan J. El-Kelani, en-us Wed, 24 Apr 2024 15:26:52 IDT Wed, 24 Apr 2024 15:26:52 IDT [email protected] [email protected] http://blogs.najah.edu/staff/radwan-el-kelani/article/Surface-Soil-Effects-Study-Using-Microtremor-Observations-in-Nablus-City-PalestinePublished ArticlesRadwan El-Kelani and Isam Jardaneh Abstract The city of Nablus is located in one of the highest seismic hazard areas in Palestine and many buildings were completely destroyed in the city during the historical earthquakes The population of Nablus city is rapidly increasing and new urbanizing areas are growing to the eastern and western parts where they are located at soft sediments Consequently the evaluation of surface soil effects is very important from a standpoint of earthquake disaster mitigation A landform classification geotechnical map was modified by analyzing available boreholes logs and seismic refraction data Microtremor measurements were carried out at about 16 sites in the study area and Nakamuras method 1989 was applied for determining predominant periods The results showed that predominant period determined at rock site in different locations of the city is about 055 sec whereas at soft soil sites in the center of the city the predominant period reaches more than 10 sec At medium soil sites mainly in the western part of the city the predominant period ranges between 065-075 sec The obvious difference of the predominant periods between hard rocks and soft soil sites reflects the surface soil cover and it coincides with the variations of geological outcrops Three main surface soil units which have different site effects were figured out from this study http://blogs.najah.edu/staff/radwan-el-kelani/article/Anatomy-of-a-Large-Fault-Zone--from-Lithospheric-to-Microscopic-Scale-The-Dead-Sea-TransformPublished ArticlesFaultshear zones FZ are the locations where movement within the Earth occurs and where motion of tectonic plates often associated with earthquakes is accommodated Despite a rapid increase in the understanding of faults in the last decades our knowledge of their form and their controlling processes remains incomplete The central questions addressed here studying the Dead Sea Transform DST in the Middle East in detail are: 1 What is the structure and dynamics of a large fault zone? 2 What controls its structure and dynamics? and 3 How does the FZ studied compare to other large fault zones? The DST has accommodated left-lateral transform motion of 105 km between the African and Arabian plates since early Miocene 20 My The DST segment between the Dead Sea and the Red Sea called AravaAraba Fault AF is studied using a multi-disciplinary and multi-scale approach from m to plate tectonic scale We show first that under the DST a narrow sub-vertical zone cuts through crust and lithosphere to more than 50 km depth The Moho increases smoothly from 26 km to 39 km under the AF from W to E and a sub-horizontal lower crustal reflector is detected east of the AF Second several faults exist in the upper crust in a 40 km wide zone centered on the AF but none has kilometer-size zones of decreased seismic velocities nor zones of high electrical conductivities typical for large damage zones The AF acts as a barrier to fluids and shows abrupt changes in lithology to a depth of 4 kilometers The AF is the main active fault of the DST system but it has only accommodated a limited part up to 60 km of the overall 105 km of sinistral plate motion Until about 5 Ma ago fault strands in the vicinity of the present day AF took up lateral motion then the main active fault trace shifted ca 1 km westward to its present position Third in the top few hundred meters of the AF a locally transpressional regime occurs in a 100 to 300 m wide zone of deformed and displaced material bordered by sub-parallel faults forming positive flower structures The damage zones of the individual faults are only 5 to 20 m wide ie significantly smaller than at other major faults Fourth two areas on the AF show meso- to micro-scale faulting and veining in limestone sequences with faulting depths between 2 and 5 km Fluids in the AF are of marine origin of Pliocene age some originated from meteoric fluids carried downward into the fault zone and to a lower extent from ascending hydrothermal fluids; but on kilometer-scale the AF does not act as an important fluid conduit Furthermore hydro-thermal reactions do not change the strength and behavior of the narrow and strong AF Fifth Most of these findings are corroborated using thermo-mechanical modeling showing that shear deformation in the lithosphere under the DSTAF trace first localizes in a 20 to 40 km wide zone with a mechanically weak decoupling zone extending sub-vertically through the entire lithosphere As time progressed upper crustal deformation became quickly focused in a few faults On plate tectonic scale the AF is a system of predominantly strike-slip faulting with less than 3 km transform-perpendicular extension Prominent similarities between the DST and the SAF are the asymmetry in sub-horizontal lower-crustal reflectors and deep reaching deformation zones Comparing the AF and the SAF at Parkfield also shows that both faults do not act as important fluid conduits at crustal scale and that both have flower structures in transpressional regimes at local scale Such features are most likely fundamental characteristics of large transform plate boundaries American Geophysical Union AGU in presshttp://blogs.najah.edu/staff/radwan-el-kelani/article/Crustal-structure-of-the-southern-Dead-Sea-basin-derived-from-project-DESIRE-wide-angle-seismic-dataPublished ArticlesAs part of the DESIRE project a 235 km long seismic wide-angle reflection refraction WRR profile was completed in spring 2006 across the Dead Sea Transform DST in the region of the southern Dead Sea basin The DST with a total of about 107 km multi-stage left-lateral shear since about 18 Ma ago accommodates the movement between the Arabian and African plates It connects the spreading centre in the Red Sea with the Taurus collision zone in Turkey over a length of about 1100 km With a sedimentary infill of about 10 km in places the southern Dead Sea basin is the largest pull-apart basin along the DST and one of the largest pull-apart basins on Earth The WRR measurements comprised 11 shots recorded by 200 three-component and 400 one-component instruments spaced 300 m to 12 km apart along the whole length of the E-W trending profile Models of the P-wave velocity structure derived from the WRR data show that the sedimentary infill associated with the formation of the southern Dead Sea basin is about 85 km thick beneath the profile With around an additional 2 km of older sediments the depth to the seismic basement beneath the southern Dead Sea basin is about 11 km below sea level beneath the profile In contrast the interfaces below about 20 km depth including the top of the lower crust and the Moho show less than 3 km variation in depth beneath the profile as it crosses the southern Dead Sea basin Thus the Dead Sea pull-apart basin is essentially an upper crustal feature with N-S upper crustal extension associated with the left-lateral motion along the DST The boundary between the upper and lower crust at about 20 km depth acts as a decoupling zone Below this boundary the two plates move past each other in what is essentially a shearing motion Thermo-mechanical modelling of the Dead Sea basin supports such a scenariohttp://blogs.najah.edu/staff/radwan-el-kelani/article/The-DESIRE-Airborne-gravity-project-in-the-Dead-Sea-Basin-and-3D-numerical-gravity-modelingPublished ArticlesThis geo-scientific research focuses on the geological setting of the Dead Sea Transform DST and the Dead Sea Basin DSB and its resulting pull-apart basins Since the late 1970s crustal scale geophysical experiments have been carried out in this region However the nature of the crust underlying the eastern and western shoulders of the DSB and underneath the DST itself is still a hotly debated topic among researchers To address one of the central questions of plate tectonics How do large transform systems work and what are their typical features? An international geoscientific Dead Sea Integrated Research project DESIRE is being conducted by colleagues from Germany Israel Palestine and Jordan In order to provide a high resolution gravity database that support 3D numerical modeling and hence a more comprehensive understanding of the nature and segmentation of the DST an airborne gravity survey as a part of the DESIRE project has been carried out from February to March 2007 The airborne gravity survey covered the DST from ElatAqaba in the South to the northern rim of the Dead Sea The low speed and terrain-following helicopter gravity flights were performed to acquire the highest possible data quality In total 32 north-south profiles and 16 west-east profiles crossing the DST have been measured Most of the profiles concentrated in areas that lacked terrestrial gravity data coverage e g over the shoulders of the DSB The airborne gravity data are merged with existing conventional terrestrial data sets to provide a seamless gravity map of the area of interest Using that combined gravity dataset and DESIRE wide angle refractions seismic interpretation we modified density structures in the DSB As results we estimated that 1 the Moho depth varies from 26 km in the Israel side to 34 km in the Jordan side 2 The maximum thickness of the Dead Sea sediment Basin is about 15 km 3 The salt rock with an average thickness of about 5 km is present not only in the southern part of the DSB but also in northern part underlying the entire Dead Seahttp://blogs.najah.edu/staff/radwan-el-kelani/article/First-results-from-a-temporary-seismological-network-in-the-Southern-Dead-Sea-areaPublished Articlesnetwork was operated in the Southern Dead Sea area as a co-operation between the GFZ Germany GII Israel NRA Jordan and An-Najah National Univer-sity Palestine From October 2006 to March 2008 about 65 short period 38 and broadband 27 instruments recorded continuously the seismicity of the Dead Sea basin This investiga-tion aims in studying the deeper structure of the Dead Sea area based on the distribution of the local seismicity About 500 local events have been recorded and more than 300 have been processed up to now A dominant feature in this first part of the dataset we found a cluster of 78 earthquakes occurring in February 2007 including multiplets We determined a 1D-reference model of P- and S-velocities using Velest Kissling et al 1994 The model shows a high velocity increase between 6 and 10 km depth This could be related to a prominent reflector found in the results of the wide angle reflection experiment in the area in 2006 Mechie et al 2008 The station corrections suggest a 2D structure with the basin in the middle and the shoulders on the east and west Additionally the results are compared with receiver function and magnetotelluric studies part of the DESIRE projecthttp://blogs.najah.edu/staff/radwan-el-kelani/article/The-Dead-Sea-and-Sodom-PeoplePublished ArticlesThe origin the salinity and the relation of the Dead Sea to Sodom People have been controversial among researchers for many decades Recently the crustal structure of the Dead Sea Transform DST which forms a part of largest Tertiary rift system has been well studied and documented But the controversy still exists on the kind of punishment that was inflicted on Sodom People Most interpretations attribute the torture to supernatural miracles The present study discussed the relation between the origin of the Dead Sea and Sodom people from different points of view An attempt was made to establish a scientific scenario and imagine the torture in the context of the available religious information and geological facts What had happened to Sodom People was related to natural phenomena which could be explained and understood by human beings http://blogs.najah.edu/staff/radwan-el-kelani/article/Site-Effect-and-Expected-Seismic-Performance-of-Buildings-in-Palestine-Case-study-Nablus-and-Ramallah-citiesPublished ArticlesLocal site effect: Landslides liquefaction amplification and faulting systems play very important roles on the intensity of earthquakes Earthquake- resistant design of new structures and evaluation of the seismic vulnerability of existing buildings involves prediction of their response to site ground motions Historical references to the correlation between earthquake damage and local site condition extend back nearly 200 years Provisions that specifically accounted for local site conditions didnt appear in building codes however until the early 1910 The local site effect can be illustrated by the following: simple theoretical ground response analysis measurements of actual surface by subsurface motions at the same site and by measurements of ground surface motions from sites with different subsurface conditions The effects of local geology on ground-motion amplification and building damage were studied in Palestine- West Bank Nakamuras method of micro tremor analysis was applied in this study The measurements showed significantly higher amplification in the frequency range of building vulnerability in different parts of Nablus city This finding is consistent with the distribution of the earthquake damage grades in the urban areas struck by the 11 February 2004 earthquake ML= 52with focal depth of 11km beneath the northeastern part of the Dead Sea Basin Quite large differences in amplification between around 1 and 9 were computed between the eastern and western rims of the city The downtown built in the central part of the city on soft clay marl and valley deposits whereas the northern and southern parts of urban areas in Nablus city lying on mountains consist of consolidated carbonates bedrock In the central part of the city and at the rims where the thickness of fluvial deposits and soft formations is about 15 m amplifications between 674 and 867 for dominant natural period range of 08 - 11 sec were obtained On the southern and northern mountains which are located on limestone rocks covered with a thin layer of soil the amplification in the same frequency range was low Calculating the natural period of the existing common buildings Tb in the studied area buildings with 1012- stories by using the dynamic analysis method The values of The obtained were much closed to the site dominant natural period Ts The findings of this study indicate that the expected differences in damage grades for urban areas in Nablus city could be attributed to variations in the thickness and physical properties of Tertiary-Quaternary sediments which appear to be rather heterogeneous In addition to the site effect amplification the geology of Nablus was the main reason behind several quite large landslides happened during ten years ago in different part of the city eg White Mountain area In Ramalalh City on the other hand the whole urban areas lying on mountains consist of consolidated carbonates bedrock where the amplification was lowhttp://blogs.najah.edu/staff/radwan-el-kelani/article/Rapid-Assessment-of-Seismic-Vulnerability-in-Palestinian-Refugee-CampsPublished ArticlesCircumstances that place people at risk or what humans do both in the normal course of their lives and in response to disasters frequently magnify the vulnerability of communities Studies of historical and recorded earthquakes in Palestine demonstrate that damaging earthquakes are occurring frequently along the Dead Sea Transform: Earthquake of 11 July 1927 ML 62 Earthquake of 11 February 2004 ML 52 In order to reduce seismic vulnerability of buildings losses in lives properties and infrastructures an attempt was made to estimate the percentage of damage degrees and losses at selected refugee camps: Al Amari Balata and Dhaishe Assessing the vulnerability classes of building structures was carried out according to the European Macro-Seismic Scale 1998 EMS-98 and the Fedral Emergency Management Agency FEMA The rapid assessment results showed that very heavy structural and non structural damages will occur in the common buildings of the investigated Refugee Camps many buildings will suffer from damages grades 4 and 5 Bad quality of buildings in terms of design and construction lack of uniformity absence of spaces between the building and the limited width of roads will definitely increase the seismic vulnerability under the influence of moderate-strong M 6-7 earthquakes in the future http://blogs.najah.edu/staff/radwan-el-kelani/article/Site-Effect-and-Expected-Seismic-Performance-of-Buildings-in-Palestine--Case-Study-Nablus-CityPublished ArticlesThe effects of local geology on ground-motion amplification and building damage were studied in Palestine-West Bank Nakamura\s method of microtremor analysis was applied in this study The measurements showed significantly higher amplification in the frequency range of building vulnerability in different parts of Nablus city This finding is consistent with the distribution of the earthquake damage grades in the urban areas struck by the 11 February 2004 earthquake ML = 52 with a focal depth of 17 km beneath the northeastern part of the Dead Sea Basin Quite large differences in amplification between around 1 and 9 were computed between the eastern and western rims of the city The downtown built in the central part of the city on soft clay marl and valley deposits whereas the northern and southern parts of urban areas in Nablus city lying on mountains consist of consolidated carbonates bedrock In the central part of the city and at the rims where the thickness of fluvial deposits and soft formations is about 15 m amplifications between 674 and 867 for dominant natural period range of 08-11 sec were obtained On the southern and northern mountains which are located on limestone rocks covered with a thin layer of soil the amplification in the same frequency range was low Calculating the natural period of the existing common buildings Tb in the studied area buildings with 10-12 stories by using the dynamic analysis method The values of Tb obtained were much closed to the site dominant natural period Ts The findings of this study indicate that the expected differences in damage grades for urban areas in Nablus city could be attributed to variations in the thickness and physical properties of Tertiary-Quaternary sediments which appear to be rather heterogeneous 2008 SEISMIC ENGINEERING CONFERENCE: Commemorating the 1908 Messina and Reggio Calabria Earthquake AIP Conference Proceedings Volume 1020 pp 191-198 2008 http:dxdoiorg10106312963829 http://blogs.najah.edu/staff/radwan-el-kelani/article/Interpretation-of-gravity-data-in-the-Jericho-area-Dead-Sea-TransformPublished ArticlesA detailed gravity survey was conducted in this study More than 100 new gravity stations with an average spacing of about 05 km were measured Qualitative interpretation of the compiled Bouguer anomaly map in the Jericho area is presented The most prominent feature of the Bouguer anomalies is the presence of negative values mainly trending in the NNE-SSW direction This trend reaches a horizontal gravity gradient of up to 10 mGalkm towards east High negative anomalies of about -30 mGal are observed to occur along the eastern side caused by thick low-density young sediments filled in the Dead Sea rift Wavelength filtering technique was used to analyze the gravity data in order to separate the effect of regional structures from that of local geologic features The residual anomaly map shows positive and negative anomalies that differ in their amplitudes sizes and trends possibly due to lateral lithological variations in the subsurface geology within the upper most part of the crusthttp://blogs.najah.edu/staff/radwan-el-kelani/article/Integrated-3D-density-modelling-and-segmentation-of-the-Dead-Sea-TransformPublished ArticlesA 3D interpretation of the newly compiled Bouguer anomaly in the area of the Dead Sea Rift is presented A high-resolution 3D model constrained with the seismic results reveals the crustal thickness and density distribution beneath the AravaAraba Valley AV the region between the Dead Sea and the Gulf of AqabaElat The Bouguer anomalies along the axial portion of the AV as deduced from the modelling results are mainly caused by deep-seated sedimentary basins D 10 km An inferred zone of intrusion coincides with the maximum gravity anomaly on the eastern flank of the AV The intrusion is displaced at different sectors along the NNWSSE direction The zone of maximum crustal thinning depth 30 km is attained in the western sector at the Mediterranean The southeastern plateau on the other hand shows by far the largest crustal thickness of the region 3842 km Linked to the left lateral movement of approx 105 km at the boundary between the African and Arabian plate and constrained with recent seismic data a small asymmetric topography of the Moho beneath the Dead Sea Transform DST was modelled The thickness and density of the crust suggest that the AV is underlain by continental crust The deep basins the relatively large intrusion and the asymmetric topography of the Moho lead to the conclusion that a small-scale asthenospheric upwelling could be responsible for the thinning of the crust and subsequent creation of the Dead Sea basin during the left lateral movement A clear segmentation along the strike of the DST was obtained by curvature analysis: the northern part in the neighbourhood of the Dead Sea is characterised by high curvature of the residual gravity field Flexural rigidity calculations result in very low values of effective elastic lithospheric thickness t e 5 km This points to decoupling of crust in the Dead Sea area In the central AV the curvature is less pronounced and t e increases to approximately 10 km Curvature is high again in the southernmost part near the Aqaba region Solutions of Euler deconvolution were visualised together with modelled density bodies and fit very well into the density model structures International Journal of Earth Sciences Volume 96 Number 2 April 2007 289-302 http:wwwspringerlinkcomcontenta181w88822619023http://blogs.najah.edu/staff/radwan-el-kelani/article/The-Dead-Sea-Desiccation-and-the-Proposed-Canal-Red-Dead-Sea-Published Articles The existence of the Dead Sea is seriously threatened by desiccation Many studies have been carried out in this regard but most of them are not well documented This paper reviewed and discussed the previous studies and focused on the natural and the political causes of the desiccation during the past periods It discussed also the different proposed projects regarding the Red-Dead Sea Canal as a solution for the desiccation problem All the historical political and environmental implications of the projects have been presented It was concluded that this solution would harm the Palestinian and Arab interests http://blogs.najah.edu/staff/radwan-el-kelani/article/Shallow-architecture-of-the-Wadi-Araba-fault-Dead-Sea-Transform-from-high-resolution-seismic-investigationsPublished ArticlesIn a high-resolution small-scale seismic experiment we investigated the shallow structure of the Wadi Araba fault WAF the principal fault strand of the Dead Sea Transform System between the Gulf of AqabaEilat and the Dead Sea The experiment consisted of 8 sub-parallel 1km long seismic lines crossing the WAF The recording station spacing was 5m and the source point distance was 20m The first break tomography yields insight into the fault structure down to a depth of about 200m The velocity structure varies from one section to the other which were 1 to 2km apart but destinct velocity variations along the fault are visible between several profiles The reflection seismic images show positive flower structures and indications for different sedimentary layers at the two sides of the main fault Often the superficial sedimentary layers are bent upward close to the WAF Our results indicate that this section of the fault at shallow depths is characterized by a transpressional regime We detected a 100 to 300m wide heterogeneous zone of deformed and displaced material which however is not characterized by low seismic velocities at a larger scale At greater depth the geophysical images indicate a blocked cross-fault structure The structure revealed fault cores not wider than 10m are consistent with scaling from wear mechanics and with the low loading to healing ratio anticipated for the fault Tectonophysics Volume 432 Issues 1-4 5 March 2007 Pages 37-50 http:dxdoiorg101016jtecto200612006http://blogs.najah.edu/staff/radwan-el-kelani/article/------ndash-Published Articlesاهتمت عدد من الدراسات بمشكلة جفاف البحر الميت وأثارها السلبية وانعكاساتها البيئية والاقتصادية والسياسية، ولكنها افتقرت في غالبها إلى الموضوعية والتوثيق الدقيق جاء هذا البحث ليقف على حقيقة المعلومات الواردة في الدراسات السابقة وأن يتناولها بالتمحيص والتدقيق كما ناقش البحث مشكلة جفاف البحر الميت بأبعادها الطبيعة والسياسية، مع الوقوف على آثارها المباشرة وغير المباشرة التي تمثلت في طرح مشروع قناة البحرين \الأحمر- الميت\ كحل للمشكلة حيث بينت هذه الدراسة أخطار هذا المشروع وتداعياته السلبية على المصالح الفلسطينية والعربيةhttp://blogs.najah.edu/staff/radwan-el-kelani/article/Seismic-Wide-Angle-Reflection--Refraction-Profiling-from-the-DESIRE-Project-Reveals-the-Deep-Structure-Across-the-Southern-Dead-Sea-BasinPublished ArticlesAs part of the DESIRE project a 240 km long seismic wide-angle reflection refraction WRR profile was completed in spring 2006 across the Dead Sea Transform DST in the region of the southern Dead Sea basin The DST with a total of about 105 km multi-stage left-lateral shear since about 18 Ma ago accommodates the movement between the Arabian and African plates It connects the spreading centre in the Red Sea with the Taurus collision zone in Turkey over a length of about 1100 km With a sedimentary infill of about 10 km in places the southern Dead Sea basin is the largest pull-apart basin along the DST and one of the largest pull-apart basins on Earth The WRR measurements comprised 11 shots recorded by 200 three-component and 400 one- component instruments spaced 300 m to 12 km apart along the whole length of the E-W trending profile Models of the P-wave velocity structure derived from the WRR data show that the sedimentary infill associated with the formation of the southern Dead Sea basin is about 85 km thick beneath the profile With around an additional 2 km of older sediments the depth to the seismic basement beneath the southern Dead Sea basin is about 11 km below sea level beneath the profile In contrast the interfaces below about 20 km depth including the top of the lower crust and the Moho show less than 3 km variation in depth beneath the profile as it crosses the southern Dead Sea basin Thus the Dead Sea pull-apart basin is essentially an upper crustal feature with N-S upper crustal extension associated with the left-lateral motion along the DST The boundary between the upper and lower crust at about 20 km depth must act as a decoupling zone Thermo-mechanical modelling of the Dead Sea basin supports such a scenariohttp://blogs.najah.edu/staff/radwan-el-kelani/article/Small-scale-gravity-modeling-of-upper-crustal-structures-in-the-Araba-Valley-along-the-Dead-Sea-TransformPublished ArticlesA detailed three-dimensional 3-D gravity model of upper crustal structures was created for the Dead Sea Transform in the ArabaArava Valley located some 80 km south of the Dead Sea Basin The density model covers an area of 30 30 km and incorporates results from several recent geophysical experiments performed in this region The model presented is a local density model that focuses on the uppermost crustal layers to a depth of 5 km Therefore in order to separate the effect of regional structures such as the crust-mantle boundary from that of local structures within the crust a residual anomaly was computed from a newly compiled Bouguer gravity anomaly database In contrast to the Bouguer anomaly which is negative across the entire study area the residual gravity field contains both positive and negative values The 3-D structural image of the upper crust reveals that the basement east and west of the Dead Sea Transform is vertically offset by 15 to 28 km Considering the 105 km of sinistral displacement of the Dead Sea Transform this result confirms the findings of other geophysical measurements that show an abrupt change in the physical parameters and geometry of the two lithological blocks that are juxtaposed along the Dead Sea Transform Additionally analysis of the calculated gravity gradients suggests that the Dead Sea Transform and the neighboring Zofar fault could be offset at depth with respect to the present-day traces at the surface Tarov Z H-J Gtze R El-Kelani J Ebbing and M Hassouneh 2006 Small-scale gravity modeling of upper crustal structures in the Araba Valley along the Dead Sea Transform Geochem Geophys Geosyst 7 Q09012 doi:1010292005GC001229 http:wwwaguorgpubscrossref20062005GC001229shtmlhttp://blogs.najah.edu/staff/radwan-el-kelani/article/A-Seismic-Profile-Across-the-Southern-Dead-Sea-BasinPublished ArticlesAs part of the DESIRE project seismic wide-angle reflection refraction WRR and near-vertical incidence reflection NVR measurements were completed in spring 2006 across the Dead Sea Transform DST in the region of the southern Dead Sea basin The DST with a total of about 105 km multi-stage left-lateral shear since about 18 Ma ago accommodates the movement between the Arabian and African plates It connects the spreading centre in the Red Sea with the Taurus collision zone in Turkey over a length of about 1100 km With a sedimentary infill of about 10 km in places the southern Dead Sea basin is the largest pull-apart basin along the DST and one of the largest pull-apart basins on Earth The WRR measurements comprised 11 shots recorded by 200 three-component and 400 one-component instruments spaced 300 m to 12 km apart along the whole length of the E-W trending 240 km long profile The NVR measurements were carried out along the central 100 km of the E-W trending profile and consisted of a 90-fold vibroseis survey along the western 50 km and an 18-fold explosive source survey along the eastern 50 km of the profile First results of modelling of the P-wave WRR data and a field example from the NVR data will be presented Together with results from previously completed seismic profiles in the region these new results will constrain models of the formation of the Dead Sea Transform DST in the region of the southern Dead Sea basinhttp://blogs.najah.edu/staff/radwan-el-kelani/article/3-dimensional-gravity-Model-of-the-southern-Jordan-Dead-Sea-TransformPublished Articles A three-dimensional interpretation of the newly compiled Bouguer anomaly map of the Dead Sea Transform DST is presented A high-resolution 3-D model constrained with the seismic results reveals a possible crustal thickness and density distribution beneath the Rift The negative Bouguer anomalies -130 mGal along the axial portion of the Rift floor as deduced from the modelling results are mainly caused by deep seated basins of light sediments 10 km The inferred zone of intrusion coincides with the maximum gravity anomaly over the eastern flank of the Rift The intrusion is displaced at different sectors along the NW-SE direction The zone of the maximum crustal thinning 30 km is attained in the western sector at the Mediterranean The southeastern plateau on the other hand shows by far the largest crustal thickness in the region 38-42 km Linked to the left lateral movement of ~ 107 km at the boundary between the African and Arabian plates and constrained with recent seismic data a small asymmetric topography of the Moho beneath the DST was modelled The thickness and densities of the crust ranging from 2650-2900 kgm suggest that the DST underlain by a continental crust The deep basins the relatively large nature of the intrusion and the asymmetric topography of the Moho lead to the conclusion that a small-scale asthenospheric upwelling? might be responsible for the thinning of the crust and subsequent rifting of the DST during the left lateral movement http://blogs.najah.edu/staff/radwan-el-kelani/article/Dead-Sea-Earthquake-of-11-February-2004-ML-52-post-earthquake-damage-assessmentPublished ArticlesABSTRACT: The 11 February 2004 earthquake ML 52 with an epicenter in the northeastern part of the Dead Sea basin at latitude 31679 N longitudes 35585 E with a focal depth of 17 km caused slight damage to several regions in the West Bank Palestine The earthquake was felt in the Palestinian cities: Jericho Hebron Nablus Ramallah Bethlehem and Jerusalem but no life loss was reported Moreover few smaller earthquakes followed the Earthquake of 11 February 2004 at different locations and times of the same year 2004: 7 July ML 48 Lat 3197 Long 3555 20 July ML 36 3246 3525 2 December ML 28 3225 3537 They mainly felt in the northern part of West Bank especially in Nablus City although they are not closed to Nablus but because of some site effects factors geological formations structures etc Based on post-earthquake investigations many reinforced concrete buildings in Palestine suffered slight non-structural damages damage grade 1 according to European Macro seismic scale 1998 EMS-1998 such as hair-line cracks in very few walls specially over frame members or in walls at the base and fine cracks in partition walls Three old schools suffered moderate structural damages and substantial non-structural damages damage grade 3 The Earthquake affected also many old masonry buildings in the Palestinian old cities Jerusalem Nablus Hebron Bethlehem etc in Nablus city few historical buildings have been affected with damages between grade 2 to grade 4 The damages that had been occurred had usually been at zone of pre-existing weakness In the light of the post-earthquake investigations the effected masonry and old masonry buildings suffered with many kinds of damages such as: crack patterns in masonry pillars slippage between the block corner detachment a flat vaults collapse detachment between few perpendicular walls in a corner and crushing in masonry pillarshttp://blogs.najah.edu/staff/radwan-el-kelani/article/3-dimensional-mapping-of-landslide-in-Nablus-City-Palestine-a-preliminary-risk-assessmentPublished ArticlesAbstract The complex nature of many landslides necessitates the need for investigating their characteristics It becomes important that the internal structure of the landslide and its surrounding environment be determined in order to facilitate reliable stability analyses and risk mitigation Models of landslide structure have traditionally been constructed based on geomorphic observations with the aid of subsurface data obtained by boreholes excavations and when possible by geophysical surveys A landslide located on the White Mountain in Nablus city Palestine is used as a case study to demonstrate the utility of a geophysical approach to subsurface mapping of unstable slopes A total of 960 m profiles were collected using Seismic refraction method Seismic data were interpreted based on stratigraphic and geomorphologic observations and then integrated into a 3-dimentional model constrained with geologic data from 10 boreholes penetrated the landslide and adjacent terrain Surfaces of rupture and separation were successfully identified by seismic refraction techniques which was effective for resolving stratigraphic relationships between units to a maximum depth of 35 m The landslide is also analyzed using PCTANI GALENA V3 software to put the various classes of parameters in order of its significance to the process of landsliding landslide susceptibility mapping and weigh the impact of one parameter against another The results of this study describe the slop-instability processes and geological hazards affecting the housing on the White Mountain and the surrounding urban areas http://blogs.najah.edu/staff/radwan-el-kelani/article/Crustal-shear-velocity-structure-across-the-Dead-Sea-Transform-from-two-dimensional-modelling-of-DESERT-project-explosion-seismic-dataPublished ArticlesAn analysis of the shear S waves recorded during the wide-angle reflectionrefraction WRR experiment as part of the DESERT project crossing the Dead Sea Transform DST reveals average crustal S-wave velocities of 33-35 km s-1 beneath the WRR profile Together with average crustal P-wave velocities of 58-61 km s-1 from an already published study this provides average crustal Poissons ratios of 026-027 V-pV-s = 176-178 below the profile The top two layers consisting predominantly of sedimentary rocks have S- wave velocities of 18-27kms-1 and Poissons ratios of 025-031 V-pV-s = 173-191 Beneath these two layers the seismic basement has average S-wave velocities of around 36 km s-1 east of the DST and about 37 km s-1 west of the DST and Poissons ratios of 024-025 V-pV-s = 171-173 The lower crust has an average S-wave velocity of about 375 km s-1 and an average Poissons ratio of around 027 V-pV-s = 178 No Sn phase refracted through the uppermost mantle was observed The results provide for the first time information from controlled source data on the crustal S-wave velocity structure for the region west of the DST in Israel and Palestine and agree with earlier results for the region east of the DST in the Jordanian highlands A shear wave splitting study using SKS waves has found evidence for crustal anisotropy beneath the WRR profile while a receiver function study has found evidence for a lower crustal high S-wave velocity layer east of the DST below the profile Although no evidence was found in the S-wave data for either feature the S-wave data are not incompatible with crustal anisotropy being present as the WRR profile only lies 30 degrees off the proposed symmetry axis of the anisotropy where the difference in the two S-wave velocities is still very small In the case of the lower crustal high S-wave velocity layer if the velocity change at the top of this layer comprises a small first-order discontinuity underlain by a 2 km thick transition zone instead of just a large first-order discontinuity then both the receiver function data and the WRR data presented here can be satisfied Finally the S-wave velocities and Poissons ratios which have been derived in this study are typical of continental crust and do not require extensional processes to explain themhttp://blogs.najah.edu/staff/radwan-el-kelani/article/Three-dimensional-Gravity-Model-of-the-southern-Jordan-Dead-Sea-TransformPublished ArticlesA three-dimensional interpretation of the newly compiled Bouguer anomaly map of the Dead Sea Transform DST is presented A high-resolution 3-D model constrained with the seismic results reveals a possible crustal thickness and density distribution beneath the Rift The negative Bouguer anomalies -130 mGal along the axial portion of the Rift floor as deduced from the modelling results are mainly caused by deep seated basins of light sediments 10 km The inferred zone of intrusion coincides with the maximum gravity anomaly over the eastern flank of the Rift The intrusion is displaced at different sectors along the NW-SE direction The zone of the maximum crustal thinning 30 km is attained in the western sector at the Mediterranean The southeastern plateau on the other hand shows by far the largest crustal thickness in the region 38-42 km Linked to the left lateral movement of ~ 107 km at the boundary between the African and Arabian plates and constrained with recent seismic data a small asymmetric topography of the Moho beneath the DST was modelled The thickness and densities of the crust ranging from 2650-2900 kgm suggest that the DST underlain by a continental crust The deep basins the relatively large nature of the intrusion and the asymmetric topography of the Moho lead to the conclusion that a small-scale asthenospheric upwelling? might be responsible for the thinning of the crust and subsequent rifting of the DST during the left lateral movement An-Najah University Journal for Research - Natural Sciences A ISSN: 1727-2114 Volume 19 2005 Pages: 185-207http://blogs.najah.edu/staff/radwan-el-kelani/article/Local-site-effects-in-Palestinian-cities-a-preliminary-study-based-on-Nablus-earthquake-of-July-11-1927-and-the-earthquake-of-February-11-2004Published ArticlesIn recent years there has been a great deal of interest to assess the local site response which is one of the key components of any seismic risk analysis The empirical method is one of the several techniques to compute the spectral ratios of horizontal and vertical components HV using microtremor records a method proposed by Nakamura 1989 Recent studies of large destructive earthquakes have shown that damage during the earthquakes are often caused by the amplification of seismic waves in near-surface sedimentary layers Studies of historical earthquakes for the past few thousand years demonstrate that the damaging earthquakes in Palestine were located along the Dead Sea Transform DST fault In the past century a destructive earthquake has occurred in the Jordan rift region at the boundary between the Arabian and the SinaiPalestine plates: Nablus earthquake of 11 July 1927 north Jericho M 62 The most recent earthquake of 11 February 2004 Mb 51 also in the Dead Sea Region about 16 km south of Jericho city with a focal depth of 21 km caused some partially damage cases; in Nablus city few historical buildings have been affected with damages between grade 2 to grade 4 according to EMS-98 A study on the HV ratio of microtremor motion at the rock substratum is presented using records from 3-component digital seismograph installed in two Palestinian cities: Nablus and Ramallah Spectral ratios were computed for different sedimentary sites where the youngest sediments of Quaternary alluvium and alternating layers of unconsolidated sedimentary materials give the highest amplification factors Our results show a good correlation between the site amplification and the damage areas of Nablus earthquake of 11 July 1927 and the disastrous effects of the recent earthquake of 11 February 2004 1st International Conference of Applied Geophysics for EngineeringOctober 13-15 2004 http://blogs.najah.edu/staff/radwan-el-kelani/article/Boundary-layer-mantle-flow-under-the-Dead-Sea-transform-fault-inferred-from-seismic-anisotropyPublished Articles Lithospheric-scale transform faults play an important role in the dynamics of global plate motion Near-surface deformation fields for such faults are relatively well documented by satellite geodesy strain measurements and earthquake source studies 12 and deeper crustal structure has been imaged by seismic profiling 3 Relatively little is known however about deformation taking place in the subcrustal lithospherethat is the width and depth of the region associated with the deformation the transition between deformed and undeformed lithosphere and the interaction between lithospheric and asthenospheric mantle flow at the plate boundary Here we present evidence for a narrow approximately 20-km-wide subcrustal anisotropic zone of fault-parallel mineral alignment beneath the Dead Sea transform obtained from an inversion of shear-wave splitting observations along a dense receiver profile The geometry of this zone and the contrast between distinct anisotropic domains suggest subhorizontal mantle flow within a vertical boundary layer that extends through the entire lithosphere and accommodates the transform motion between the African and Arabian plates within this relatively narrow zone At the southern end of the Dead Sea transform DST between the Dead Sea and the Red Sea the Wadi Arava fault is the main active strike-slip fault 46 trending approximately N20E Near the Figure 1 Study area and shear-wave splitting parameters a Map with topography and the locations of seismic stations for which the shear-wave splitting analysis was performed The Arava fault black line strikes at approximately N20E The bars indicate measured SKS splitting parameters for the period range of 25 s blue and 57 s red The orientation corresponds to the polarization direction of the fast shear wave fast polarization f and the length is proportional to the delay time dt1 s b Measured shearwave splitting parameters circles along the profile delay times and fast polarization directions for the two period bands 25 and 57 s The parameters are obtained by application of an inverse splitting operator to minimize the energy of the transverse SKS component 17 A measure of error has been derived from the 95 confidence region as determined by the x 2 distribution For reasons of representation a factor of 04 is applied to the error scales used in this figure The lines represent a smoothed version of the measurements calculated by averaging the results within a sliding window http://blogs.najah.edu/staff/radwan-el-kelani/article/Geophysical-images-of-the-Dead-Sea-Transform-in-Jordan-reveal-an-impermeable-barrier-for-fluid-flowPublished Articles High-resolutionseismictomography and magnetotelluric MT soundings of the shallow crust show strong changes in material properties across the Dead Sea Transform Fault DST in the Arava valley in Jordan 2D inversion results of the MT data indicate that the DST is associated with a strong lateral conductivity contrast of a highly conductive layer at a depth of approximately 15 km cut-off at a position coinciding with the surface trace of the DST At the same location we observe a sharp increase of P wave velocities from 4 kms west of the fault to 5 kms to the east The high velocities in the east probably reflect Precambrian rocks while the high electrical conductivity west of the DST is attributed to saline fluids within the sedimentary filling In this sense the DST appears to act as an impermeable barrier between two different rock formations Such a localized fluid barrier is consistent with models of fault zone evolution but has so far not been imaged by geophysical methods The situation at the DST is remarkably different from active segments of the San Andreas Fault which typically show a conductive fault core acting as a fluid conduit INDEX TERMS: 1515 Geomagnetism and Paleomagnetism: Geomagnetic induction; 7205 Seismology: Continental crust 1242; 8005 Structural Geology: Folds and folding; 8180 Tectonophysics: Tomography Citation: Ritter O T Ryberg U Weckmann A Hoffmann- Rothe A Abueladas Z Garfunkel and DESERT Research Group Geophysical images of the Dead Sea Transform in Jordan reveal an impermeable barrier for fluid flow 3014 1741 doi:1010292003GL017541 2003 http://blogs.najah.edu/staff/radwan-el-kelani/article/Modelling-of-seismic-guided-waves-at-the-Dead-Sea-TransformPublished Articles On several recordings of linear seismometer arrays crossing the Arava Fault AF in the Middle East we see prominent wave trains emerging from in-fault explosions which we interpret as waves being guided by a fault-zone related low-velocity layer The AF is located in the Arava Valley and is considered the principal active fault of the mainly N-S striking Dead Sea Transform System in this section Observations of these wave trains are confined to certain segments of the receiver lines and occur only for particular shot locations They exhibit large amplitudes and are almost monochromatic We model them by a 2D analytical solution for the scalar wavefield in models with a vertical waveguide embedded in 2 quarter spaces A hybrid search scheme combining genetic algorithm and a local random search is employed to explore the multimodal parameter space Resolution is investigated by synthetic tests The observations are adequately fit by models with a narrow only 3 to 12 m wide waveguide with S-wave velocity reduced by 10 to 60 of the surrounding rock We relate this vertical low-velocity layer with the damage zone of the AF since the location of receivers observing and of shots generating the guided waves respectively match with the surface trace of the fault The thickness of the damage zone of the AF at least at shallow depths seems to be much smaller than in other major fault zones This could be due to less total slip on this fault http://blogs.najah.edu/staff/radwan-el-kelani/article/The-crustal-structure-of-the-Dead-Sea-TransformPublished ArticlesTo address one of the central questions of plate tectonicsHow do large transform systems work and what are their typical features?seismic investigations across the Dead Sea Transform DST the boundary between the African and Arabian plates in the Middle East were conducted for the first time A major component of these investigations was a combined reflectionrefraction survey across the territories of Palestine Israel and Jordan The main results of this study are: 1 The seismic basement is offset by 35 km under the DST 2 The DST cuts through the entire crust broadening in the lower crust 3 Strong lower crustal reflectors are imaged only on one side of the DST 4 The seismic velocity sections show a steady increase in the depth of the crust-mantle transition Moho from 26 km at the Mediterranean to 39 km under the Jordan highlands with only a small but visible asymmetric topography of the Moho under the DST These observations can be linked to the left-lateral movement of 105 km of the two plates in the last 17 Myr accompanied by strong deformation within a narrow zone cutting through the entire crust Comparing the DST and the San Andreas Fault SAF system a strong asymmetry in subhorizontal lower crustal reflectors and a deep reaching deformation zone both occur around the DST and the SAF The fact that such lower crustal reflectors and deep deformation zones are observed in such different transform systems suggests that these structures are possibly fundamental features of large transform plate boundaries Geophysical Journal International Volume 156 Issue 3 Pages 655 - 681 http:www3intersciencewileycomjournal118792617abstract http://blogs.najah.edu/staff/radwan-el-kelani/article/3D-Gravity-Field-Modelling-of-the-Lithosphere-along-the-Dead-Sea-Transform-DESERT-2002Published ArticlesFrom March to May 2002 a gravity field campaign has to be conducted in the area of Dead Sea RiftDead Sea Transform with regard to the isostatic state the crustal density structure of the transform and the lithospheric rigidity in the Central Arava Valley Jordan Our multi-national and interdisciplinary gravity group with participants from the Geophysical Institute of Israel the Natural Resources Authority Jordan and the An-Najah National University Palestine takes part in the interdisciplinary and international DESERT program which is coordinated by the GeoForschungsZentrum GFZ Potsdam Germany The study area is located about 100 km away from both the basin of the Dead Sea and the Gulf of ElatAqaba basin respectively Between March and May 2002 some 800 new gravity observations were recorded at a local scale in the Arava valley and at regional scale along the DESERT seismic line Station spacing in the area of the Arava valley was 100 - 300 m and in the nearest neighbourhood of the fault 50 m only The survey of detailed observations covered an area of 10 by 10 km and was completed by a likewise dense survey at the western side of the valley in Israel All gravity data were tied to the IGSN -71 gravity datum and are terrain-corrected as well The station complete Bouguer gravity field Free air anomaly and residual isostatic anomalies based on both Airy and Vening-Meinesz models were merged with the existing regional gravity data bases of the region Constraining information for the 3D density models came from recent geophysical field data acquisition and consist of seismic seismological electromagnetic studies and geological mapping which represent the integrated part of the interdisciplinary research program Novel methods eg curvature techniques and Euler deconvolution of the gravity fields shed new insight into the structure of upper and lower crust and the causing density domains In particular the dip-curvature reveal a clear course of underground structures which could be linked to the Arava fault system with their pull-apart structures The results of preliminary 3D density models which are constrained by the seismic refraction and reflection profile of the DESERT program and seismic tomography show a good correlation with the near surface velocity field in the area of the Arava fault and a slightly different picture of the Moho at a depth of interface which stemmed from refraction modelling along the principal DESERT reflection and refraction seismic line EGS - AGU - EUG Joint Assembly Abstracts from the meeting held in Nice France 6 - 11 April 2003 abstract 7785 http://blogs.najah.edu/staff/radwan-el-kelani/article/Crustal-structure-along-the-DESERT-2000-Transect-inferred-from-3-D-gravity-modellingPublished ArticlesA three-dimensional interpretation of the newly compiled Bouguer anomaly map is part of the DESERT 2000 Transect That is multi-disciplinary and multinational project studying for first time the Dead Sea Transform DST fault system DST from the Mediterranean Sea to Saudi Arabia across the international border in the NW-SE direction The negative Bouguer anomalies with magnitude reached C130 mGal located into transform valley are caused by the internal sedimentary basins filled by the light density young sediments Y10 km A high-resolution 3-D model constrained with the seismic results reveals a possible crustal thickness and density distribution beneath the DST valley The inferred zone of intrusion coincides with the maximum gravity anomaly over the eastern flank of the DST The intrusion is displaced at different sectors along the NW-SE direction The zone of the maximum crustal thinning 30 km is attained in the western sector at the Mediterranean The southeastern plateau on the other hand shows by far the largest crustal thickness in the region 38-42 km Linked to the left lateral movement of ~ 105 km at the boundary between the African and Arabian plate and constrained with the DESERT 2000 seismic data a small asymmetric topography of the Moho beneath the DST was modelled The thickness and density of the crust suggest that a continental crust underlies the DST The deep basins the relatively large nature of the intrusion and the asymmetric topography of the Moho lead to the conclusion that a small-scale asthenospheric upwelling? might be responsible for the thinning of the crust and subsequent rifting of the Dead Sea graben during the left lateral movement American Geophysical Union Fall Meeting 2003 abstract S21F-0399 http://blogs.najah.edu/staff/radwan-el-kelani/article/Modeling-of-seismic-guided-waves-at-the-Dead-Sea-TransformPublished ArticlesOn several recordings of linear seismometer arrays crossing the Arava Fault AF in the Middle East we see prominent wave trains emerging from in-fault explosions which we interpret as waves being guided by a fault zone related low-velocity layer The AF is located in the Arava Valley and is considered the principal active fault of the mainly N-S striking Dead Sea Transform System in this section Observations of these wave trains are confined to certain segments of the receiver lines and occur only for particular shot locations They exhibit large amplitudes and are almost monochromatic We model them by a two-dimensional 2-D analytical solution for the scalar wave field in models with a vertical waveguide embedded in two quarter spaces A hybrid search scheme combining genetic algorithm and a local random search is employed to explore the multimodal parameter space Resolution is investigated by synthetic tests The observations are adequately fit by models with a narrow only 3-12 m wide waveguide with S wave velocity reduced by 10-60 of the surrounding rock We relate this vertical low-velocity layer with the damage zone of the AF since the location of receivers observing and of shots generating the guided waves respectively match with the surface trace of the fault The thickness of the damage zone of the AF at least at shallow depths seems to be much smaller than in other major fault zones This could be due to less total slip on this fault Journal of Geophysical Research Solid Earth Volume 108 Issue B7 pp ESE 7-1 CiteID 2342 DOI 1010292002JB002309 http:dxdoiorg1010292002JB002309