Active Deformation of the Central and Northern Dead Sea Fault

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0106238Muawia BarazangiThe Dead Sea Fault System (DSFS) is one of the largest continental strike-slip faults in the world. As the transform plate boundary between the Arabian and African plates, the DSFS represents a key tectonic feature in the eastern Mediterranean region. Despite its tectonic significance, the understanding of the DSFS as an active, seismogenic structure is relatively limited, particularly along the central and northern sections of the fault in Syria and Lebanon. Through an interdisciplinary study of DSFS in Syria and Lebanon, the ongoing research is addressing several important issues including:(1) Whether or not northern DSFS deformation fully accounts for Arabia-Africa plate motions and, hence, represents the present-day plate boundary.(2) How predictions of northward increase in slip rate and fault-normal convergence (suggested by plate tectonic models) are reflected in DSFS kinematics.(3) The role of earthquakes in plate boundary deformation along a major continental transform (the DSFS) including fault segmentation and aseismic strain release.(4) The relationship of internal deformation of the adjacent Arabian plate to kinematic variations along the DSFS, and the connection between the DSFS and the Arabian-Eurasian collision.In order to bridge the critical gap that typically exists between neotectonic and geodetic/seismological assessments of strain, results of this neotectonic and geodetic work are currently integrated with a lengthy, well-documented historical record of large earthquakes (approximately M 6.5) spanning at least the past 2,000 years. Such a lengthy historical record spanning multiple earthquake cycles is generally unavailable along almost any other major plate boundary.To address the issues outlined above, the following is being accomplished:(1) Regional mapping of the active branches of the DSFS using all available remote sensing data (including aerial photos and a high-resolution elevation models produced using InSAR) to determine geometric (and possible seismogenic) segments.(2) Local studies of key fault segments (detailed mapping, surveying fault-related landforms, and paleoseismic studies) in order to delimit: long-term fault slip rates and kinemetrics (103 - 106 years); earthquake histories and recurrence over many earthquake cycles (Holocene to present), and; past earthquake sizes and their distribution along fault segments. Historical earthquake data place further limits on earthquake size and recurrence during the past ~2,000 years.(3) Tectonic geodesy (primarily GPS) in the far-field and near-field to determine short-term rates of fault slip and kinematics (several years), possible aseismic slip vs. strain accumulation, and possible internal deformation of the northern Arabian plate.Integrating and modeling neotectonic, geodetic, and historical data for the DSFS provide new insight on the kinematics and dynamics of DSFS with broader implications for active strike-slip faults, in general. Furthermore, the results of this study have significance for regional earthquake hazard assessment in Syria and Lebanon, as well as neighboring countries, where large, rapidly expanding populations heighten the need for accurate earthquake hazard assessments. The collaborative study builds upon past and ongoing joint research involving Cornell, MIT, IPG Strasbourg, and Syrian and Lebanese institutions.(4) The relationship of internal deformation of the adjacent Arabian plate to kinematic variations along the DSFS, and the connection between the DSFS and the Arabian-Eurasian collision.In order to bridge the critical gap that typically exists between neotectonic and geodetic/seismological assessments of strain, results of this neotectonic and geodetic work are currently integrated with a lengthy, well-documented historical record of large earthquakes (approximately M 6.5) spanning at least the past 2,000 years. Such a lengthy historical record spanning multiple earthquake cycles is generally unavailable along almost any other major plate boundary.To address the issues outlined above, the following is being accomplished:(1) Regional mapping of the active branches of the DSFS using all available remote sensing data (including aerial photos and a high-resolution elevation models produced using InSAR) to determine geometric (and possible seismogenic) segments.(2) Local studies of key fault segments (detailed mapping, surveying fault-related landforms, and paleoseismic studies) in order to delimit: long-term fault slip rates and kinemetrics (103 - 106 years); earthquake histories and recurrence over many earthquake cycles (Holocene to present), and; past earthquake sizes and their distribution along fault segments. Historical earthquake data place further limits on earthquake size and recurrence during the past ~2,000 years.(3) Tectonic geodesy (primarily GPS) in the far-field and near-field to determine short-term rates of fault slip and kinematics (several years), possible aseismic slip vs. strain accumulation, and possible internal deformation of the northern Arabian plate.Integrating and modeling neotectonic, geodetic, and historical data for the DSFS provide new insight on the kinematics and dynamics of DSFS with broader implications for active strike-slip faults, in general. Furthermore, the results of this study have significance for regional earthquake hazard assessment in Syria and Lebanon, as well as neighboring countries, where large, rapidly expanding populations heighten the need for accurate earthquake hazard assessments. The collaborative study builds upon past and ongoing joint research involving Cornell, MIT, IPG Strasbourg, and Syrian and Lebanese institutions.