Figure 13. Correlation of results among paleoseismic trenching, archaeoseismic excavations, and tufa analysis. In paleoseismic trenching, the youngest age for
event X is not constrained, but it is, however, limited by event Y. In archaeoseismic excavations, the period of fi rst damage overlaps with that of the second damage due to
poor age control. In tufa analysis, the onset and restart of Br-3 and Br-4 mark the damage episodes to the aqueduct; the growth of Br-5 and Br-6 shows interruptions (I)
indicating the occurrence of major events. Except for the 29 June 1170 event, previous events have been unknown in the historical seismicity catalogue. The synthesis of
large earthquake events results from the timing correlation among the faulting events, building repair, and tufa interruptions (also summarized in Fig. 12 and text).
Although visible in trenches (faulting event X), archaeoseismic excavations (first damage), and first interruption of tufa growth (in Br-5 and Br-6 cores), the A.D. 160–510
age of event X has a large bracket. In contrast, event Y is relatively well bracketed between A.D. 625 and 690, with the overlapped dating from trench results, the second
damage of the aqueduct, and the interruption and restart of Br-3 and onset of Br-4. The occurrence of the A.D. 1170 earthquake correlates well with event Z from the trenches,
the age of third damage to the aqueduct, and the age of interruption of Br-4, Br-5, and Br-6.
Sbeinati et al (2010)
Figure 12. (A) Calibrated dating of sam-ples (with calibration curve INTCAL04 from Reimer et al. [2004] with 2 sigma age range and 95.4% probability)
and sequential distribution from Oxcal pro¬gram (see also Table 1; Bronk Ramsey, 2001). The Bayesian distribution com¬putes the time range of
large earthquakes (events W, X, Y, and Z) at the Al Harif aqueduct according to faulting events, construction and repair of walls, and starts and
interruptions of the tufa deposits (see text for explanation). Number in brackets (in %) indicates how much the sample is in sequence; the number in
% indicates an agreement index of overlap with prior distribution.
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Figure 15. Estimated fault-slip behavior and related slip rates (obtained from regression lines) from two scenarios of possible earthquake occurrence
taking into account timing for paleo-earthquakes as in Figure 12 (with average X [A.D. 160–510] 375 ± 175, average Y [A.D. 625–690] 640 ± 32, Z [A.D. 1170], and two
different time frames for W [historical event of 1365 B.C. and 962 B.C.). In both cases, the two regression lines indicate a minimum and maximum slip-rate estimate.
In parallel, we assume an average 4.3 m characteristic individual slip consistent with the cumulative 13.6 m measured on the aqueduct (Fig. 5). If we assume a minimum
age A.D. 962 for W (according to the dating in unit f, related rate of sedimentation, and the interface between unit f and unit g in trench C), the slip rate ranges
between 6.1 mm/yr and 6.3 mm/yr (dark regression line with 80% correlation coefficient), implying that a large seismic event is overdue. If we consider the historical
catalogue and the 1365 B.C. earthquake sequence along the Dead Sea fault for W (gray regression line with 78% correlation coefficient), the slip rate reduces to 4.9–5.5 mm/yr.
The question mark indicates that for both scenarios, a large earthquake is overdue along the Missyaf fault segment (according to the seismic gap and the 4.0 m slip defi cit).
The temporal cluster of three large earthquakes in less than 1000 yr suggests a Wallace model of fault behavior with periods of seismic quiescence reaching ~1700 yr.
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Figure 14. Schematic reconstruction (with final stage from Fig. 5) of the A.D. 160–510, A.D. 625–690, and A.D. 1170 large earthquakes and related faulting of the Al Harif aqueduct.
Except for the A.D. 1170 earthquake (see historical cata-logue of Sbeinati et al., 2005), the dating of earthquake events are from Figure 12. The white small section is the rebuilt wall after
event X (see buried wall A and B in Fig. 8B); the subsequent gray piece corresponds to the rebuilt wall after event Y (see wall section C in Fig. 8B), which was damaged and dragged after event Z.
The earlier aqueduct deformation (warping of the eastern wall near the fault rupture) may have recorded ~4.3 m of coseismic left-lateral slip that remained relatively well preserved during the subsequent fault movements.
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