Event F at Nahal Ze'elim site ZA-1 a 15 cm thick Type IV seismite with an estimated intensity of 9. ZA-1 was the first site in Nahal Ze'elim to be systematically investigated for Holocene paleoseismicity and established the basic framework for correlating earthquake-generated deformation structures with the historical earthquake record of the Dead Sea region. The site occupies a relatively landward position within the Ze'elim Terrace compared with the more seaward exposures examined in later studies such as Kagan et al. (2011). As a result, ZA-1 contains a greater proportion of shoreline and nearshore facies, whereas the later studies accessed more seaward sections characterized by thicker and more continuous lacustrine deposition. These more offshore settings preserved a larger number of earthquake-induced deformation horizons, resulting in a more complete Holocene paleoseismic record than was available at ZA-1.
Event F occurs in northern gully, within the upper part of the Ze'elim Formation, ~520 cm above the base of the northern gully, and above the major mid-first millennium CE erosional unconformity that removed much of the record between the ~4th and ~11th centuries CE. The lithology in this portion of the section differs from that of the lower, predominantly lacustrine interval, containing a higher proportion of detrital sediment. Event F is expressed as a mixed layer composed of disturbed fine-grained sediment and fragmented aragonite laminae. As with the older mixed layers in the section, the deformation is interpreted as the result of earthquake-induced liquefaction, fluidization, brecciation, and resuspension of unconsolidated sediment at the sediment-water interface, followed by resettling on the lake floor.
The age of Event F was constrained using three radiocarbon determinations obtained from within the mixed layer. These yielded ages of 780 ± 30 (sample KIA3214A), 660 ± 30 (sample KIA3215), and 680 ± 30 (sample KIA3216) radiocarbon years BP. However, Ken-Tor et al. (2001a) considered the 780 ± 30 BP (sample KIA3214A) determination to be out of stratigraphic order and interpreted it as reworked material. Excluding this anomalous date, the remaining determinations yielded a calibrated age range of 1270-1400 CE ( 2σ). Including sample KIA3214A leads to a calibrated 2σ range of 1210-1400 CE. Although either range overlaps substantially with that of Event E (1220-1390 CE), the two mixed layers are separated by approximately 20-30 cm of detrital sediment. Based on estimated sedimentation rates of roughly 3-13 mm yr-1, this intervening deposit represents approximately 20-100 years of accumulation, supporting the interpretation that Events E and F record two separate earthquakes rather than a single event. On the basis of their stratigraphic order and the historical interval between major regional earthquakes, Ken-Tor et al. (2001a) correlated Event E with the 1212 CE earthquake and Event F with the 1293 CE earthquake. The correlation of Event F with the 1293 CE earthquake was retained by Ken-Tor et al. (2001b).
- Fig. 1c Oblique aerial photo of
SW Dead Sea showing Masada and Zeelim Plain from Agnon et al. (2006)
An oblique air photo looking southward at the southwestern part of the Dead Sea showing faults (solid lines) and locations of studied late Pleistocene sections M and PZ. MFZ—Masada Fault Zone. The photo was taken in 1940 when the lake level was 395 m below sea level. The current level is 420 m below sea level; additional area has emerged, including the Ze' elim fan outcrop.
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Agnon et al. (2006)- Nahal Ze'elim outcrop areas
in Google Earth
ZA-I is a guesstimate
click on image to explore this site on a new tab in Google Earth- Figure 2 Annotated Lithosection
of ZA-1 with interpreted ages noted from Ken-Tor et al. (2001a)
The lithology and chronology of a composite section exposed in Ze'elim Plain. The section is described from two outcrops exposed in different gullies 300 m apart. The correlation between the outcrops is based on the sedimentary sequence, laminae counting, and 14C dates. Ages presented in 14C years B.P. Deformed units (mixed layers and liquefied sands) are marked by capital letters.
slightly modified by JW - red dates as interpreted by JW added
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Ken-Tor et al. (2001a)- Figure 8 Age Model for ZA-1
from Agnon et al. (2006)
A modified age model for the Ze'elim section studied in outcrop (Ken-Tor et al., 2001a) and drill core (Migowski et al., 2004). A–H denote events discussed in the text. The present model was constrained by two rules:
(1) each event horizon (top of each intraclast breccia) matches a historical earthquake of notice.
(2) each continuous deposition segment shows a uniform deposition rate.
Two outcomes support the model. Two of the breccia layers match pairs of earthquakes (64–31 BCE; 1202–1210 CE) such that the earlier event horizon is within the breccia layer and the later event matches the top. With these assignments for the event horizons, the model gives a uniform sedimentation rate of 0.5 cm/yr during the three periods separated by hiatuses.
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Agnon et al. (2006)- Figure 3 Age Model for ZA-1
from Ken-Tor et al. (2001a)
Table 1
- Chronology of the deformed units (seismites) in the Ze'elim section. Solid dots represent 14C ages in years B.P. Error bars represent the ranges in the calibrated ages (2σ) of all samples in each stratigraphic horizon. Vertical thin lines represent historical earthquakes in the Dead Sea area, which were correlated to the deformed units in the Ze'elim section. Horizontal dashed arrows are drawn from the deformed units (listed in capital letters) to the correlative earthquakes.
- Sedimentation rates calculated for the lower part of the composite section. The longest calibrated range was used for calculating the minimum sedimentation rate, and the shortest range for calculating the maximum sedimentation rate. Two clear unconformities are evident. The upper one is dated to 1290-1420 A.D., and the lower one to 1030-1210 A.D. The lower unconformity is marked by a sharp decrease in the sedimentation rate. Vertical dashed lines represent earthquakes that lie within the sedimentological hiatuses. Sedimentation rate of the upper part of the section was not calculated because datable samples were insufficient.
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Ken-Tor et al. (2001a)- Table 1 Radiocarbon Table
from Ken-Tor et al. (2001b)
AMS results of 14C dating. Calibrated dates according to Stuiver et al. (1998). The samples are listed by stratigraphic height, from top to bottom. Samples collected from seismite units are shown in bold.
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Ken-Tor et al. (2001b)- Table 1 Radiocarbon Table
from Ken-Tor et al. (2001a)
AMS Results of Radiocarbon Dating
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Ken-Tor et al. (2001a)- Table 2 Refined Radiocarbon Table
from Ken-Tor et al. (2001a)
The 14C Chronology of the Deformed Layers (Seismites)
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Ken-Tor et al. (2001a)- Figure 4e Calibrated Radiocarbon Ages
from Ken-Tor et al. (2001b)
Chronology of the seismite record
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Ken-Tor et al. (2001b)- Fig. 2 Sediment Core comparisons
and Age-Depth Models for Ein Gedi, En Feshka, and Nahal Zeelim from Migowski et al. (2004)
Lithology of the sediment cores and the established age-depth models of the different profiles. The Ze'elim coring profile is paralleled by the Ze'elim gully wall. The Ein Gedi chronology is based on 20 radiocarbon dates and on the varve-counted section (black line) in the upper part.
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Migowski et al. (2004)- Correlated Trench Logs used
to Produce Composite ZA-1 Litholog from Revital Bookman (née Ken-Tor)
The final lithosection of Bookman (née Ken-Tor) is a composite litholog derived from multiple sites located up to approximately 300 m apart. ZA-1 refers to the location from which a large portion of the composite lithosection was constructed. More landward gullies were used to capture the most recent earthquakes, including Events G (1834 CE) and H (1927 CE). Bookman referred to site ZA-1 as Site 2.
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Revital Bookman (née Ken-Tor)