Event ST4 was identified in Trench T4 at Tell Saidiyeh, a site situated along the Jordan Valley Fault. Unlike the purpose-excavated Trench T3, Trench T4 originated as a cut made during agricultural leveling works and trends northwest–southeast, oblique to the fault trace. The exposure was subsequently widened and cleaned by Ferry et al. (2011). The trench exposes a well-developed fault zone affecting both late Pleistocene and Holocene deposits. Because the trench is oriented approximately 45° to the fault, the deformation zone appears wider than in a perpendicular exposure and provides an unusually detailed record of repeated surface ruptures.
The evidence for Event ST4 consists of a conspicuous group of minor fault splays in the southeast part of the trench affecting a distinct subhorizontal layer within unit o. According to Ferry et al. (2011:54), these splays demonstrate that faulting occurred after deposition of unit o. However, subsequent erosion removed the upper portion of the deformed deposits and truncated all of the fault splays at a later erosional surface. The rupture therefore survives only as a partially preserved event horizon, with much of its original stratigraphic context having been destroyed by younger geomorphic processes.
The interpretation of Event ST4 depends heavily on reconstruction of the sedimentary history of the trench. Ferry et al. observe that the older channel system composed of units n, m, and l cut deeply into units o and p and completely removed unit o from the western part of the trench. Because the fault splays associated with Event ST4 are truncated by this erosional episode, the earthquake must have occurred before deposition of the channel-fill sequence and unit n. This relationship demonstrates that the rupture predates one of the major episodes of channel incision and sediment reworking preserved within the Tell Saidiyeh stratigraphy.
The chronology of Event ST4 is difficult to constrain because the erosion that followed the earthquake removed much of the associated stratigraphic record and limited the availability of datable material. According to Ferry et al. (2011:54-55), the available evidence permits only a broad age bracket of 12,060 BCE to 10,910 BCE identical to that proposed for Event TT4. The authors note, however, that the main channel fill was probably considerably thicker than the portion presently exposed. If this inference is correct, Event ST4 would lie stratigraphically closer to sample L-06 (11790-11310 BCE) and therefore nearer the older end of the 12,060 BCE to 10,910 BCE bracket. They consequently suggest that the earthquake most likely occurred between approximately 12,060 BCE and 11,500 BCE.
- Fig. 3b Location Map of the
Tell Saidiyeh Site from Ferry et al. (2011)
Geomorphology of the Tell Saidiyeh site from a high-resolution total station topographic survey (contour spacing 0.5 m). South of the archaeological tell (located ~100 m to the north; see inset in Fig. 8b), the morphology displays a recent terrace strath (Qto) affected and left-laterally displaced by the fault. The southern edges (dashed lines) of streams serve as piercing points because they are less likely to be eroded than the northern ones in a left-lateral setting. Stream El flows westward along the southern edge of Qto and is displaced by 7 ± 0.5 m across the fault. Stream W2 is a beheaded remnant of El and displays 114 ± 5 m of offset. A minimum emplacement age of 22 ka for W2 yields an average slip rate of 4.9 mm/yr for that period. Solid rectangles represent trenches T3 and T4, which display faulting evidence for the last 17 ka. Blanked areas could not be surveyed because of the presence of agricultural and military facilities.
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Ferry et al. (2011)- Fig. 5E Stratigraphic Correlation
between Ghor Khabed and Tell Saidiyeh Trenches from Ferry et al. (2011)
Correlations of stratigraphic sections of trenches. The geological formations of Lisan and Damya are common basement-bottom units for trenches. Erosion processes (tilde lines) have major effects on soft sediments, and Trench T3 shows a significant hiatus of the Damya formation. The correlation between alluvial and lacustrine deposits and the related radiocarbon dating (see also Table 1 and Fig. 7) illustrate the different recent depositional environments at trench sites.
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Ferry et al. (2011)- Table 1 Radiocarbon Table
from Ferry et al. (2011)
Radiocarbon Dating of Samples Collected in Trenches T1 and T2 (Ghor Kabed Site) and T3 and T4 (Tell Saidiyeh Site)
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Ferry et al. (2011)- Fig. 4a Oblique view of trench
T4 showing Lisan units affected by faulting and liquefaction from Ferry et al. (2011)
Oblique view of trench T4 showing Lisan units affected by faulting and liquefaction in the foreground and sand and silt units in the background
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Ferry et al. (2011)- Fig. 4b Main Shear Zone of trench
T4 from Ferry et al. (2011)
The main shear zone [of Trench T4) is outlined by a 1-cm-thick layer of crushed sand (thick lines) and displays numerous oriented pebbles.
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Ferry et al. (2011)Fig. 5d
Trench T4 is originally a road cut that was noticeably extended and cleaned. It is oriented 45° to the fault, which widens the deformation zone. This exposure provides the bulk of the paleoseismic dataset. See text for details.
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Ferry et al (2011)
