Event 1 was identified in trench T-20, which was excavated on the Avrona playa in the central part of the Elat fault zone. The Avrona playa forms one of several en echelon tectonic basins bound by subparallel left-stepping faults. It is a 10-km-long and 0.5–2-km-wide basin crossed diagonally by the north-northeast- trending Elat fault zone and presently forms a broad, elongated ridge characterized by low subridges and shallow braided channels draining toward the Gulf of Elat (aka Gulf of Aqaba) through the Elat coastal sabkha.

This part of the Elat fault zone is characterized by sinistral strike-slip faulting accompanied by local compressional and extensional structures, including push-ups, pull-aparts, and normal faults. Shallow seismic reflection data show that the Elat fault zone is several hundred meters wide and consists of several subparallel, north-northeast-trending fault splays, including flower structures. Amit et al. (2002) note that these subsurface structures are generally consistent with the mapped surface traces across the alluvial-fan surfaces and playa deposits. Trench T-20 was excavated across what was interpreted as the youngest fault scarp in the Avrona playa, exposing a multiple-event normal fault with one principal fault plane. Amit et al. (2002) identified five partially preserved colluvial units (units I–V in Figure 10 below) adjacent to the fault plane. These colluvial wedges were interpreted as deposits formed during repeated episodes of surface- rupturing fault displacement. Although Amit et al. (2002:202) conclude that at least six surface-rupturing earthquakes affected the Avrona playa during the past 14 ka—represented by the five colluvial units and a younger surface-rupturing event— Amit et al. (2002:Table 1) only provide specific ages and displacement estimates for the three youngest of these earthquakes, spanning the period between 6800 BCE and ~1000 CE (8.8 to ~1 ka). Amit et al. (1999:Table 3) notes that the three older events responsible for colluvial units I-III date to between 10200 and 4800 BCE (10.1 ± 2.1 ka to 8.7 ± 1.9 ka) and produced vertical displacements between 50 and 90 cm each. Amit et al. (1999:Table 3) also noted an even earlier seismic event responsible for initial downfaulting of the eastern part of the trench sometime between 13500 and 6000 BCE (between 14.2 ± 1.3 and 10.1 ± 2.1 ka).

According to Amit et al. (2002:Table 1), Event 1 dates to 5800-4400 BCE (7.1 ± 0.7 ka). Dating was based on based on IRSL and pedogenic interpretation. The event produced an estimated maximum vertical displacement of 0.5 m. If the Wells and Coppersmith (1994) maximum-displacement relation for normal faults is applied, 0.5 m of vertical displacement implies an estimated moment magnitude of approximately M_W 6.4.

• Fig. 3 Location Map for Trench T-20
  Figure 3
  
  Air photo of the Avrona playa showing the traces of the photogrametric topographic profiles (circles) and the sites of the trenches and exposures (rectangles) described in the text. The straight lineament that bounds and crosses the playa (dark area)represents a NNE-trending fault of the Avrona Shear Zone. This fault is trenched in T-20. The dark area bounded by straight lineaments corresponds to the uplifted sterile playa sediment. The light-tone areas mark the wide braided Wadi Avrona stream, which occupies a structural depression in the north and splits into several narrow and shallow streams within the playa area. The main faults are designated A–E; the profiles are labelled GI-0061, GI-0065 andGI-0074.
  
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  Zilberman et al. (2005)
  from Zilberman et al. (2005)
• Fig. 2 Geomorphic Map of the
  Figure 2
  
  Geomorphic map of the southern Arava valley in the Avrona basin.
  
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  Zilberman et al. (2005)
  southern Arava from Zilberman et al. (2005)

Figure 10

Log of the southern wall of trench T-20, across a fault scarp in the Avrona playa. The location of trench T-20 is shown in Figure 2.

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Amit et al. (2002)