Introduction
The Dead Sea Transform (DST) is a principal continental transform fault, extending roughly 1,000 km from the Marash triple junction in southeastern Turkey to the northern reach of the Red Sea Rift off Sinai. It marks the plate boundary between the African Plate to the west and the Arabian Plate to the east and accommodates predominantly left-lateral (sinistral) strike-slip motion. Geodetic (GPS) measurements show both plates migrating north–northeast, with the Arabian Plate advancing more rapidly; this differential motion has produced cumulative sinistral offsets on the order of ~107 km toward the southern part of the system. Along-strike kinematics vary: the southern sector is transtensional, generating a series of pull-apart basins and depressions (notably the Gulf of Aqaba, the Dead Sea basin, the Sea of Galilee, and the Hula basin), whereas the Lebanon restraining bend imposes transpressional shortening that uplifts flanking regions such as the Beqaa Valley. At the northern terminus, localized transtension created the Ghab pull-apart basin, illustrating how changes in fault strike and obliquity of plate motion produce alternating zones of extension and compression. The DST is therefore best viewed as a segmented fault system whose geometry, segmental behavior, and regional effects are constrained by structural mapping and GPS-derived velocity vectors, linking strike-slip kinematics to characteristic geomorphic and topographic responses and to contemporary political boundaries in the southern sector.
Tectonic interpretations of the Dead Sea Transform (DST) converge on two end‑member models that carry distinct geological and geodynamic consequences. The prevailing view treats the DST as a long‑lived left‑lateral transform accommodating roughly 105 km of northward displacement of the Arabian Plate relative to Africa. This interpretation is supported by displaced geomorphic and cultural markers—river terraces, gullies and archaeological structures—whose systematic horizontal offsets yield long‑term average slip rates of the order of a few millimetres per year when integrated over the last several million years. Contemporary geodetic (GPS) measurements record present‑day relative motion at comparable rates, providing independent confirmation that lateral plate translation remains active along the DST corridor.
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An alternative hypothesis interprets parts of the fault zone as an incipient rift or nascent spreading center linked to the Red Sea Rift. Under this model the dominant processes would be extensional: crustal thinning, magmatism and progressive development of oceanic lithosphere rather than simple strike‑slip displacement. These competing frameworks therefore predict different subsurface structures, seismic behaviour and surface morphologies.
Resolving whether the DST functions principally as a transform or as a rift has direct implications for regional geodynamics, seismic and volcanic hazard assessment, and reconstructions of paleogeography. The transform model explains linear lateral offsets and strike‑slip seismicity; the rift model implies enhanced magmatic activity and potential seafloor spreading. Quantifying the timing and magnitude of displacement over million‑year timescales is thus essential for interpreting past landscape evolution, displacement of archaeological sites, and present‑day tectonic risk along the Arabian–African plate boundary.
The development of the Dead Sea Transform (DST) records a multi-stage evolution from broad regional uplift/subsidence to an interconnected strike‑slip plate boundary. Its foundations were laid during Late Eocene epeirogenic movements, with focused faulting and the onset of strike‑slip behaviour occurring in the Oligocene and continuing through the Miocene. A reorganization of plate kinematics in the Early–Middle Miocene (∼23–11.6 Ma) curtailed active rifting in the Gulf of Suez and shifted deformation from rift‑dominated extension to transform‑dominated displacement along the DST.
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In its early propagation phase the transform system migrated northward well beyond the Dead Sea region, reaching southernmost Lebanon; cumulative relative offset for this stage is estimated at ~64 km. During the Late Miocene, however, continued plate‑boundary slip was largely taken up by crustal shortening in the Palmyra fold belt of central Syria, producing a temporal pulse in which contractional deformation rather than strike‑slip motion accommodated much of the regional strain. Renewed northward propagation in the Pliocene extended the DST through Lebanon into northwestern Syria and ultimately linked it to the East Anatolian Fault, thereby completing the northward connection between the transform system and the Anatolian plate boundary.
The southern section of the Dead Sea Transform (DST) is a discrete north–south–oriented tectonic segment roughly 400 km long that physically and mechanically links the Red Sea rifting system to the northern Levant. Its southern end is rooted in a Red Sea spreading center at the southern extremity of the Gulf of Aqaba, marking the divergent boundary that initiates the transform linkage. Northward, the segment terminates just north of the Hula basin in southernmost Lebanon, where the transform grades into the structural and basin architecture of the northern Levant. Collectively, these termini and the intervening strike form a continuous structural corridor coupling Red Sea spreading to deformation in the southern Levant.
The Gulf of Aqaba is an elongate marine trough whose shape and internal deformation are controlled by a series of four offset strike‑slip faults arranged in a left‑stepping echelon. The diagonal, stepwise displacement of these segments imposes the gulf’s planform and localizes strain where segments interact. At the overlaps between adjacent left‑stepping faults, the kinematics produce transtensional regimes that favor vertical subsidence and create space for sediment accumulation.
These overlap zones have evolved into discrete pull‑apart basins that define the gulf’s principal bathymetric depressions. Three principal seafloor lows—the Daka Deep, the Aragonese Deep and the Elat Deep—correspond to these localized extensional troughs formed by segment overlap and the accompanying extensional fault motion. Thus the distribution of depths along the gulf reflects the underlying segmentation and overlap geometry of the fault network.
The fault system is actively seismogenic: the 1995 Gulf of Aqaba earthquake ruptured portions of three of the four segments, illustrating how the echelon configuration channels seismic slip and determines where rupture initiates and terminates. In sum, the gulf’s bathymetry and its tendency for segmental earthquake rupture are direct consequences of the left‑stepping strike‑slip geometry, with pull‑apart basin formation and concentrated seismicity both tied to the same structural arrangement.
Wadi Arabah (Arava Valley) comprises a principal, approximately 160 km long fault corridor of the Dead Sea Transform linking the Gulf of Aqaba in the south to the southern margin of the Dead Sea. Along its strike the corridor exhibits systematic variations in fault morphology and behavior, prompting its common subdivision into two segments. The southern Avrona segment extends northward from the northern Gulf of Aqaba for roughly 50 km and defines the southern portion of the Wadi Arabah reach, whereas the Arava segment continues northward from the Avrona terminus for about 100 km and occupies the central to northern part of the valley.
Geodetic and geomorphic observations—notably measured offsets of stream gullies across the fault trace—indicate a horizontal slip rate on these segments of about 4 ± 2 mm yr−1. Paleoseismic investigations combined with historical accounts record four large ground-shaking events attributed to this fault system (1068, 1212, 1293 and 1458), demonstrating repeated large-magnitude seismicity on the Wadi Arabah segment over the last millennium.
Dead Sea basin
The Dead Sea is a classic pull‑apart basin formed where left‑stepping offsets between the Wadi Arabah and Jordan Valley strike‑slip faults produce a rhombohedral, subsiding depression. This strike‑slip geometry has generated long‑lived accommodation space along a central basin tract roughly 150 km in length and 15–17 km wide, where sedimentary fill locally exceeds 2 km; farther north the fill reaches maximum thicknesses of about 10 km. The basin’s extreme subsidence has produced the lowest land‑based elevation on Earth, making it a globally significant physiographic feature.
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The sedimentary succession records a coherent stratigraphy that documents the basin’s evolution: Miocene fluvial sandstones of the Hazeva Formation form the basal unit; these are succeeded by predominantly halitic evaporites of the Sedom Formation deposited in the Late Miocene to early Pliocene; and the evaporites are overlain by a Pliocene–recent sequence dominated by lacustrine to fluvial deposits. This stacking reflects transitions from fluvial to evaporitic to lacustrine environments as accommodation and hydrology changed through time.
Seismic and thermal observations of the basin are anomalous for a major transform: the central basin shows a relative paucity of shallow earthquakes, whereas recorded seismicity beneath the Dead Sea has a tendency for substantially greater hypocentral depths than typical transform faults. Heat‑flow measurements are unusually low compared with other strike‑slip systems (for example, the San Andreas). To reconcile the central quiescence, deep hypocentres, low heat flow, rhombohedral planform and marked subsidence, researchers have proposed a “drop‑down” or damage rheology model in which a dense magmatic lithospheric block becomes lodged near the Moho beneath the basin center. This lodged body would mechanically divert stress toward the basin margins, promote deeper earthquake nucleation, and contribute to the basin’s unusual geometry and exceptional subsidence.
Jordan Valley fault (Dead Sea Transform)
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The Jordan Valley fault constitutes a ~100 km segment of the Dead Sea Transform within the Jordan Rift Valley, extending along the valley axis from the northwestern shore of the Dead Sea toward the southeastern margin of the Sea of Galilee. Structurally it functions as a linear strike‑slip fault that links these basins and localizes seismic hazard along its trace.
Geodetic and paleoseismic measurements yield a long‑term lateral slip rate of 4.7–5.1 mm yr⁻¹ for this segment, an interval estimated over the past ~47,500 years and corresponding to an accumulated offset on the order of 223–242 m. Paleoseismic reconstructions attribute full‑segment ruptures to large medieval earthquakes, notably events dated to AD 749 and AD 1033, the latter representing the most recent major rupture of the structure. The time elapsed since AD 1033 has led to a measurable slip deficit; the stored tectonic strain on the Jordan Valley segment is assessed to be sufficient to produce a future earthquake of approximately Mw 7.4.
Sea of Galilee (Kinneret) basin
The Sea of Galilee Basin is a tectonically generated pull‑apart basin whose eastern margin is defined by the Jordan Valley fault and whose opposing boundary is accommodated by a series of smaller faults to the north. Interaction between these fault segments produced localized extension and subsidence, creating space for sediment to accumulate preferentially adjacent to the major fault.
Seismic reflection data reveal the basin’s deepest sedimentary accumulation concentrated on the eastern side, immediately against the lateral continuation of the Jordan Valley fault, indicating an asymmetric depositional architecture controlled by fault geometry. The deepest mapped seismic horizon, interpreted as the base of the sedimentary succession, corresponds to an inferred maximum fill of about 3 km and is correlated with the top of a basalt unit dated to roughly 4 Ma. This volcanic marker provides a temporal constraint on post‑basalt sedimentation and, together with the fault configuration and depocentre position, demonstrates that the basin’s stratigraphy and thickness are intimately linked to its pull‑apart tectonic evolution.
Hula basin
The Hula pull‑apart basin is a strike‑slip–related tectonic depression immediately north of the Sea of Galilee. It has formed where several short, segmented fault strands step over one another, producing localized subsidence concentrated within a relatively narrow corridor of active deformation.
The basin is bounded to the west by the Hula Western Border Fault, a principal strand that fractures and splays northward into subsidiary faults that transmit displacement along a northward fault network, notably linking into the Roum and Yammouneh strands. Its eastern limit is the Hula Eastern Border Fault, which projects northward from the northeastern Sea of Galilee margin and continues to connect with the Rachaya fault system.
Structurally, the pull‑apart results from the en echelon arrangement and connectivity of these border faults: their geometry and relative offsets control where subsidence is focused and where the narrow active deformation zone persists. Regionally, the Hula basin and its bounding faults form part of a continuous north‑trending strike‑slip corridor that transfers displacement from the Sea of Galilee area to faults farther north, thereby shaping the seismic behavior and geomorphic evolution of this sector of the Levant.
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Lebanon restraining bend
Within the Lebanon restraining bend the Dead Sea Transform (DST) diverges into multiple subsidiary fault strands rather than remaining a single continuous plane. The local change in fault geometry produces transpressional conditions that partition oblique plate motion onto a suite of strike‑slip, reverse and oblique‑slip segments. Each of these segments exhibits its own geometry, kinematic sense and temporal activity, so deformation is distributed among discrete, mappable faults rather than being concentrated on a solitary trace.
This segmentation has direct consequences for rupture behavior and seismic hazard. Segment boundaries may halt or promote the propagation of earthquakes, thereby influencing maximum event size, the routes that ruptures follow, and how slip is allocated along the system. Consequently, the restraining bend both increases the number of plausible nucleation sites and complicates estimates of recurrence intervals derived from single‑fault models.
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Field and geomorphic indicators—localized uplift, folding, fault scarps, stepover basins and diverted drainage—provide primary evidence for identifying individual active strands and comparing their activity. Robust assessment therefore requires an integrated methodology: detailed geomorphic mapping, paleoseismic trenching across scarps, continuous geodetic measurements and seismicity analysis are all necessary to delineate segment boundaries, quantify slip rates and determine how the restraining bend governs the long‑term evolution of the DST in Lebanon.
The Yammouneh fault constitutes the principal throughgoing strand of the Lebanon restraining bend and carries the bulk of plate‑boundary displacement across this portion of the regional fault network. Oriented SSW–NNE, it extends for roughly 170 km from the northwestern margin of the Hula Basin to its junction with the Missyaf Fault, and functions as the main locus of strike‑slip deformation within the bend. Paleoseismic and geodetic data yield an average slip rate of ~4.0–5.5 mm yr−1, indicating the rate at which differential motion accumulates along the structure. Long‑term recurrence estimates for large earthquakes on the Yammouneh fault are on the order of 1.02–1.175 kyr, and the fault has produced several historically documented large events, most notably the 1202 Syria earthquake. The absence of a similarly large rupture since 1202, when considered alongside the estimated recurrence interval and slip rate, implies appreciable accumulated strain on the fault and correspondingly elevated regional seismic hazard.
The Roum fault is a subsidiary strand of the Yammouneh fault that branches off at the northwestern margin of the Hula Basin, forming an integral part of the local fault network and remaining structurally linked to the Yammouneh system. Its surface trace can be followed northward for roughly 35 km, beyond which geomorphic expression becomes indistinct or obscured, indicating a segmented and partly cryptic trace along its length.
Kinematic and spatial data associate rupture on the Roum fault with the 1837 Galilee earthquake, demonstrating that this strand has participated in major historical seismic activity. Geologically derived long‑term slip‑rate estimates range between 0.86 and 1.05 mm yr−1, quantifying its contribution to regional strain accumulation. Together, these characteristics—branching geometry, measurable length, documented historical rupture, and a measurable slip rate—identify the Roum fault as an active, segmented element of the regional transform system with clear implications for seismic hazard in the Hula Basin and adjacent areas.
Rachaya–Serghaya faults
The Rachaya–Serghaya fault zone comprises two principal strands—Serghaya to the south and Rachaya to the north—that branch from the Hula Eastern Border Fault and together form a segmented tectonic system controlling deformation around Mount Hermon and the adjacent Anti‑Lebanon range. Both strands attain a generally SSW–NNE orientation where fully developed; the Serghaya strand projects northeastward from the Hula fault, passes south of Mount Hermon and, upon entering the Anti‑Lebanon, undergoes a marked strike reorientation to SSW–NNE. The Rachaya strand diverges similarly from the Hula fault but trends SSW–NNE while passing north of Mount Hermon.
Historical seismicity and measured slip highlight strand‑specific behaviour within this single regional system. Movement on the Serghaya fault has been associated with the November 1759 earthquake and yields a geologic slip rate of approximately 1.4 mm yr−1. The Rachaya fault is interpreted as the source of the October 1759 event but currently lacks a published slip‑rate estimate. The close temporal succession of large earthquakes on adjacent strands in 1759 underscores the potential for closely spaced, strand‑specific ruptures within the same fault corridor.
Tectonically, the branching pattern from the Hula Eastern Border Fault reflects segmentation and transfer of crustal strain across the Levantine margin, with the measured asymmetry in known slip rates implying partitioned motion between strands. The structural reorientation of the Serghaya as it enters the Anti‑Lebanon and the absence of a quantified rate for Rachaya identify clear targets for targeted paleoseismic trenching and modern geodetic measurement to refine recurrence intervals, assess seismic hazard, and clarify the mechanics of strain transfer between these faults.
Northern segment of the Dead Sea Transform
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The northern segment of the Dead Sea Transform (DST) extends along strike from the northern end of the Yammouneh Fault to the tectonic triple junction where the DST meets the East Anatolian Fault. This section constitutes a coherent structural corridor that mechanically and geometrically links the Yammouneh system with Anatolian faulting, defining a distinct zone of concentrated deformation within the broader DST system.
Deformation within this segment is dominated by a transpressional kinematic regime driven by oblique relative plate motion. Motion combines predominant right‑lateral strike‑slip with a significant shortening component, producing a characteristic assemblage of tectonic features: uplift and folding of sedimentary cover, thrust faulting, and localized restraining bends where shear is accommodated by compressional structures. Such mixed kinematics leads to along‑strike variability in structural style and topography.
Contemporary geodetic measurements corroborate this interpretation: GPS velocity vectors across the northern DST display an oblique convergence and shear trajectory that accounts for both the lateral displacement and the compressional strain recorded in the field. The geodetic pattern therefore links instrumentally measured plate motions to the distributed transpressional deformation observed at the surface.
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The triple junction with the East Anatolian Fault functions as a principal kinematic transfer and partitioning site. Here the DST’s transpressional regime interacts with Anatolian fault systems, producing abrupt changes in fault geometry and regional stress orientation and promoting spatial partitioning of strike‑slip versus compressive strain. Consequently, the junction is a critical locus for understanding how regional plate motions are accommodated and redistributed across adjacent fault networks.
Missyaf fault (Ghab segment)
The fault segment commonly referred to as the Ghab fault forms an approximately 70 km structural continuation from the northern terminus of the Yammouneh fault into the Ghab basin, providing a coherent crustal link between these named features. Geodetic and geological estimates yield a long‑term lateral slip rate of about 6.9 mm yr−1 along this mapped length, indicating ongoing tectonic loading and sustained crustal deformation across the segment. Paleoseismic and historical records attribute at least two very large ruptures (Mw > 7) to this structure, dated to AD 115 and AD 1170. The absence of similarly large events since AD 1170—when considered alongside the measured slip rate and the segment’s rupture potential—constitutes a pronounced seismic gap and implies accumulation of strain that could be released in a comparable large earthquake. Given its structural continuity with the Yammouneh fault and its position within the Ghab basin corridor, this segment represents a significant seismic hazard for the surrounding region, with the potential for widespread impact should a major rupture occur.
The Ghab basin is interpreted as a transtensional pull‑apart that originated in the Pliocene at the left‑stepping overlap between the Missyaf and Hacıpaşa strike‑slip faults. Localized subsidence developed where the two fault segments offset and overlapped, producing accommodation space characteristic of strike‑slip basins.
Measuring roughly 60 km long and 15 km wide, the basin’s elongated planform reflects control by the orientation and spacing of the bounding faults; the long axis tracks the strike‑slip geometry and the locus of transtensional deformation. Interpretation relies principally on seismic reflection profiles, which delineate basin geometry and internal architecture, augmented by the Ghab‑1 well that provides direct stratigraphic and chronologic tie points.
Stratigraphic evidence indicates the fill is exclusively Pliocene to recent, implying basin initiation in the Pliocene and sustained (continuous or episodic) sedimentation to the present. Internally the basin is partitioned into two main depocentres at its northern and southern ends, separated by an intrabasinal high that functions as a structural elevation or sedimentary divide. This end‑member arrangement reflects how overlap and relay between the left‑stepping Missyaf and Hacıpaşa segments partition accommodation space, control sediment thickness and facies distribution, and create intrabasinal highs where linkage structures or relay ramps interrupt continuity between depocentres.
Hacıpaşa fault
The Hacıpaşa fault is a crustal-scale, through-going structure that connects the Ghab and Amik sedimentary basins, forming a continuous trace that has likely influenced basin geometry and depositional patterns. Within the regional plate-boundary framework it functions as a principal tectonic strand, accommodating the majority of relative motion between adjacent blocks and thereby concentrating displacement along its trace. Structurally the fault is linked to the Karasu fault, indicating geometric and mechanical continuity that permits transfer of slip and stress within a linked fault system. Historical seismicity attributed to the Hacıpaşa fault — notably major events in 1408 and 1872 — attests to its capacity for generating large, damaging earthquakes and establishes a multi-century record of activity. Because of its length, through-going nature, and connection to adjacent faults, the Hacıpaşa fault increases the likelihood of extended ruptures and represents a significant seismic hazard for communities and infrastructure in and around the Ghab and Amik basins; it therefore merits central consideration in both tectonic reconstructions and regional hazard assessments.
Karasu (Amanos) fault
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The Karasu, or Amanos, fault is a principal SW–NE–striking structure that occupies the transitional zone between the Dead Sea Transform and the East Anatolian Fault, and thus plays a central role in the regional fault-network geometry. Geologically active throughout the Quaternary, it exhibits a long-term slip rate of approximately 1.0–1.6 mm yr⁻¹, indicating sustained but relatively moderate cumulative displacement during the Quaternary.
The fault has produced large earthquakes over multi-millennial and historical timescales: palaeoseismic and historical records attribute a Mw ≈7.5 event in AD 521 and a Mw ≈7.2 event in 1872 to this structure. Most recently, on 6 February 2023 the Karasu fault ruptured in a Mw 7.8 earthquake; this rupture occurred contemporaneously with breaks on the Pazarcık and Erkenek segments of the East Anatolian Fault, evidence of mechanical interaction and linked rupture behavior among adjacent segments.
Taken together, its geometry, Quaternary slip rate, and repeated large ruptures establish the Karasu/Amanos fault as an active and seismically significant component of the regional tectonic framework with a demonstrable capacity to generate major earthquakes.