Event E1 in Trench T3
Kanari et al. (2020) report that Trench T3
intersects the active
Avrona Fault in
Elat Sabkha and that Event E1 ruptured units U2–U8 in Trench T3, expressed
along faults F1–F5 and possibly F11. Four
charcoal samples—three above the event
horizon and one below—were dated by radiocarbon and
modeled using a
Bayesian model to estimate that Event E1
occurred between 897 and 992 CE
(
2σ). However, three samples that yielded
laboratory-calibrated (but not modeled) ages as old
as 661 CE and as recent as 1248 CE were rejected as
outliers, indicating that the actual time window for
this event may be broader than 897–992 CE.
Kanari et al. (2020) interpret Event E1 in
Trench T3 as a
surface-rupturing earthquake
expressed across a ~9 m wide fault zone. The
event is characterized by
distributed deformation
across multiple
fault strands,
including slight
push-up geometry in an
antiform flower structure on F1–F4 and apparent down-to-the-west vertical
separation on several other strands.
Kanari et al. (2020) interpret mismatch of
layer thickness across the fault traces as
evidence for predominantly
strike-slip motion,
while the consistent west-side-down apparent
offsets could indicate an additional
normal-slip component.
However, they note that such apparent vertical
offsets may also result from originally
irregular
fluvial stratigraphy or variations in
layer thickness, and therefore the presence and
magnitude of a normal-slip component remain
uncertain.
Kanari et al. (2020:12–13) suggest that the
1068 CE earthquake "best correlates" with
Event E1. They further correlate Elat Sabkha
Event 1 with Event E3 in the
Qatar Trench, located ~35 km to the north,
as well as with
events at Avrona Playa (Zilberman et al. 2005).
Noting that
Klinger et al. (2015) "suggest that the
surface rupture of the 1068 CE earthquake
terminated somewhere close to the Yotvata Sabkha
and their Qatar trench site,"
Kanari et al. (2020:12–13) calculate a
minimum rupture length of ~37 km and estimate a
magnitude of M = 6.6–7.1 using a
scaling relationship from
Wells and Coppersmith (1994).
