Fortress at Arad Quake

~250 BCE

by Jefferson Williams


Introduction     Textual Evidence     Archeoseismic Evidence     Tsunamogenic Evidence     Paleoseismic Evidence     Notes     Paleoclimate - Droughts     Footnotes     References


Introduction

Archeoseimic Evidence from the fortress at Tel Arad and paleoseismic evidence in the Dead Sea may indicate a mid 3rd century BCE earthquake struck the area. This may or may not be related to tsunamogenic evidence from Elat.

Textual Evidence

Archeoseismic Evidence

Fortress at Arad
Herzog, Z. (2002) interpreted damage observed at the Fortress at Tel Arad during the Hellenistic Period and attributed the damage to a strong earthquake during the middle of the 3rd century BCE. Apparent seismic damage was observed at the southern and eastern wings of the fortress and in two cisterns where roof collapse was observed. Dating this damage is based on Hellenistic pottery shards found inside a debris filled depression that was presumed to have been caused by the earthquake and late Hellenistic structures built atop this debris filled depression and elsewhere. Hellenistic Structures were dated based on toothed chisel marks. Archeoseismic evidence for a mid 3rd Century BCE earthquake can best be described as possible. Relevant sections from Herzog's report are reproduced in the Notes section of this catalog entry.

Tsunamogenic Evidence

Goodman Tchernov et al (2016) identified a paleo tsunami deposit close to Elat from two submarine cores taken at North Beach and Tur Yam locations. They described the dating as follows:
The radiocarbon age from the North Beach places the maximum age at 100–400 BC (2 sigma error), while the Tur Yam radiocarbon age brackets the horizon as a minimum age of 100–500 BC (2 sigma error). Highest probability of these two radiocarbon ages place the event at about 2300 yBP, or around 200–300 BC (Data Repository).
The tsunamite deposit in the Tur Yam core was inferred from "an anomalous bed (~60cm) of more concentrated mixed shell and broken coral fragments of varying condition from pristine to heavily worn and eroded." The inferred tsunamite deposit in the North Beach core was encountered "at a depth of 160 cm down-core [where] the grain size increases to greater than coarse sand (>250 micron) and foraminifer abundances decrease significantly to either low or barren (0–150 individuals per cm3)." The anomalous bed in the North Beach Core was ~32 cm. thick.

Paleoseismic Evidence

Bet Zayda
Wechsler at al. (2014) records event CH4-E6 (modeled age 392 BCE – 91 CE) in paleoseismic trenches at Bet Zayda just north of the Sea of Galilee (aka Lake Kinneret).
Bet Zeyda Earthquakes
Figure 9. Probability density functions for all paleoseismic events, based on the OxCal modeling. Historically known earthquakes are marked by gray lines. The age extent of each channel is marked by rectangles. There is an age uncertainty as to the age of the oldest units in channel 4 (units 490-499) marked by a dashed rectangle. Channel 1 refers to the channel complex studied by Marco et al. (2005).
En Feshka
Kagan, E., et al. (2011) report several seismites from En Feshka that might fit this earthquake. Modeled ages from Table 3 are presented below:

Depth Seismite Type & Thickness Mean Age +/- 1σ Mean Age +/- 2σ
425 cm. B - 2 cm. 222.5 BCE +/- 20.5 235.5 BCE +/- 52.5
428 cm. D - 2 cm. 232 BCE +/- 20 246.5 BCE +/- 54.5
438 cm. A & E - 2 cm. 263 BCE +/- 23 279 BCE +/- 57
447 cm. B - 2 cm. 294 BCE +/- 27 307.5 BCE +/- 58.5


Seismite Types are shown visually in Figure 2 and and are described in Table 1 of Kagan et al (2011) which is repeated below:

Type Description
A Intraclast breccia: Light and dark laminae “floating” in a dark matrix.
B Microbreccia: A light gray layer, seemingly homogeneous to the naked eye,
of intermediate color somewhere between the dark brown/gray detrital laminae
and the white/beige evaporitic laminae. Petrography shows this to be a mixture
of the evaporitic and the detrital material
C Liquefied sand
D Fold: Small-scale folds, where the amplitude is on the order of millimeters to a few centimeters
E Fault: Tiny faults, millimeter to centimeter scale throw


En Gedi
Migowski et. al. (2004) do not report a seismite in the middle of the 3rd century BCE in the 1997 GFZ/GSI core.
Nahal Ze 'elim
Kagan, E., et al. (2011) report one seismite from Nahal Ze 'elim which might fit this earthquake. Modeled ages from Table 3 are presented below:

Depth Seismite Type & Thickness Mean Age +/- 1σ Mean Age +/- 2σ
552 cm. A - 8 cm. 225 BCE +/- 35 225 BCE +/- 75


Notes

Archeoseismic Evidence from the Fortress at Arad
Relevant sections from Herzog's (2002) report on the fortress at Arad are reproduced below:
pp. 12-13

Apparent damage to the southern and eastern wings of the fortress occurred during the Hellenistic period (3rd century BCE). The massive foundations, intended to guarantee the stability of a large tower erected at the centre of the site, completely destroyed remains of earlier periods. Additional severe damage resulted from the collapse of the rock roof of two of the water cisterns (Fig. 3). This event took place during the Hellenistic period, apparently the result of a strong earthquake. The collapse caused the complete destruction of all occupational remains and created a deep depression in the northwestern sector of the fortress. The depression was partly filled in with debris and partly built over by later Hellenistic-period structures. Moreover, the levelling of the depression with debris from the close surroundings eliminated most of the upper Iron Age remains (Strata VII and VI) in this area (Fig. 4). Consequently, the Hellenistic structures were erected at elevations similar to those of the Iron Age strata elsewhere. This chaotic process is responsible for the lack of architectural remains of the Iron Age strata in this area.
p 74

Based on evidence provided by the only intact cistern, the subterranean reservoir consisted of elliptical cisterns. There appear to have been three cisterns. The rock ceilings of two of these collapsed during the Hellenistic period. The considerable thickness of the rock layer that remained above the reservoir (approximately 2 m.) indicates that the collapse was not a result of the pressure of settlement layers, but the consequence of a powerful earthquake.
p 76

The water system of Arad is a unique example of a water storage system combined with a postern for emergency use. An earthquake apparently caused the collapse of the Arad water system as well as other systems in the south. From the excavations at Masada and Qumran, we know that earthquakes occurred during the 2nd and 1st centuries BCE (Karcz and Kafri 1978). During that same period, the water system at Tel Beersheba was also destroyed. Such a date is supported by the late Hellenistic sherds found amid the debris in depressions created as a result of the collapse (Fig. 4, above). The same episode probably also caused the collapse of the well in the lower city.

Paleoclimate - Droughts

Footnotes

References