2nd Earthquake
Kázmér et al. (2024:33)
proposed that two separate earthquakes affected
Umm al-Jimal, the second occurring toward the end
of the
Umayyad Caliphate.
They estimated a local
intensity
of IX for this later event.
Archaeoseismological indicators for both episodes
included
tilted and bulged walls,
U-shaped collapse features,
and evidence of
rotational and extensional deformation.
Al-Tawalbeh et al.
(2019) described similar deformation in the
Barracks, including tilted and bulging walls,
U-shaped collapses,
twisted walls,
torsion-related damage,
and displaced
ashlars.
Although they did not associate these effects
with a specific event, they suggested that they
most likely resulted from the second earthquake.
In both cases, the second earthquake was suspected
to be one of the
749 CE Sabbatical
Year Earthquakes.
Osinga in
Lichtenberger and Raja (2025:194) cautions,
however, that “while the AD 749 earthquake may
have caused destabilization of some structures
and collapse of certain features,” such as
portions of the Numerianos Church, “the
archaeological record reveals no significant
destruction that can be conclusively and solely
dated to the mid-eighth century.”
This uncertainty stems largely from chronological
difficulties.
Osinga in
Lichtenberger and Raja (2025:184, 184 n. 8)
explains that early
Abbasid
pottery shows strong continuity with late Umayyad
pottery, and significant changes to the ceramic
record do not appear until around the turn of the
ninth century.
She also points out that Umm al-Jimal suffers
from a lack of coin-secured deposits or other
chronologically significant finds. Although some
earlier scholars speculated that Umm al-Jimal may
have been abandoned after the
749 CE Sabbatical
Year Earthquakes,
Osinga in
Lichtenberger and Raja (2025:194) concluded
that “we simply cannot characterize or date the
departure of the sedentary populace from Umm
al-Jimal, other than to state that it almost
certainly occurred prior to the ninth century.”
She adds that whether this abandonment was a slow
or rapid process, and what the underlying causes
were, must remain open to discussion.
That said, archaeoseismic evidence at Umm
al-Jimal is extensive, and if the sedentary
population had abandoned or largely abandoned
the site by the ninth century CE, the absence of
later repairs has effectively preserved traces
of earlier seismic activity—likely including
evidence from one of the
749 CE Sabbatical
Year Earthquakes—even if that evidence cannot
be dated with certainty.
One of the better-dated contexts is the Roman
Temple which, according to
Osinga in
Lichtenberger and Raja (2025:186), “was later
converted into a domestic structure known as
House 49.” This building contained
Byzantine
and
Early Islamic
debris, and
Osinga in
Lichtenberger and Raja (2025:187) note
collapsed architecture on the porch (loci
036 and 040) that “may date to the Early
Islamic period.”
Another somewhat well-dated location is the
Numerianos Church complex, where heavy
architectural collapse is noted directly
above floors last used in the Umayyad period,
establishing a mid-eighth-century CE
terminus
post quem
for the major collapse observed in this
complex.
Osinga in
Lichtenberger and Raja (2025) also report
possible mid-eighth-century archaeoseismic
evidence in House 119.