Bet Zeyda Earthquakes
Figure 8b

Tying the offsets to event ages. The events that were recognized by Wechsler et al. (2014) are represented by their age probability density functions (pdfs) as generated by Oxcal, and color coded by channel. For each event, an associated offset is attached. Colored boxes at the top represent the age extent of each channel's sediments. Historically known earthquakes are marked by grey lines. There is an age uncertainty as to the age of the oldest units in channel 4 (units 490–499) marked by a dashed rectangle. Inset – the result of the CVt calculation for the earthquake ages.

JW: Shape of events at 1202 and 1759 on this plot understate uncertainty and present unrealistic probability distributions - because these two events came from older work where such a probability density vs. time plot wasn't generated. Event E.H. 1 dates to between 1020 and 1280 CE and very likely reflects the 1202 CE earthquake. Event E.H.2 struck after 1415 CE but it is not known how long after. It could have been a result of a number of different earthquakes such as the 1546, 1759, and 1837 earthquakes. Marco et al (2005) favored the 1759 CE earthquake but considered the possibility of other earthquakes.

Wechsler at al. (2018)


Summary of 2D and 3D Paleoseismic Study at Bet Zayda

Results are based on a 3D paleoseismic study conducted over multiple years, utilizing multiple trenches, and performed by multiple researchers at Bet Zeyda (aka Beteiha) just north of the Sea of Galilee (aka Lake Kinneret). Trenches were dug to examine paleo-channels which intersect and were offset by the active Jordan Gorge Fault. Initial work was done by Marco et al (2005). At Marco et al (2005)'s northern site, they identified two fault ruptures which exhibited a similar temporal pattern to two fault ruptures at the Tel Ateret archaeoseismic site ~12 km. to the north. In their radiocarbon derived age-depth model for Bet Zayda, Event E.H. 1 was tightly dated (1020 - 1280 CE) and likely was caused by the 1202 CE earthquake. Event E.H. 2 was not tightly dated. It struck sometime after 1415 CE. Marco et al (2005) suggested that one of the Baalbek Quakes of 1759 CE was responsible for E.H. 2, but they considered other possibilities such as the 1546 CE and 1837 CE earthquakes. Information from Marco et al (2005)'s work is summarized below:

Seismic Events from Marco et al (2005)
Event Date Range Quake assignment Displacement (m) Estimated Magnitude Notes
E.H. 1 1020-1280 CE 1202 CE ~2.2 7.1 - 7.3 Sinistral Slip
E.H. 2 after 1415 CE 1759 CE 0.5 6.6 - 6.9 Sinistral Slip
Another channel from their southern site trenches was sinistrally displaced ~15 meters in the past 5 ka. Its dip slip was 1.2 m with the west side down. This indicated that 12.3 m of sinistral slip accumulated between 5 ka and just before the 1202 CE earthquake. Subsequent work at the same location (northern site) by Wechsler at al. (2014) revealed 8 more surface-rupturing earthquakes with a total of 5.2 m of displacement. These additional events extended the record back by ~1100-1600 years. Seismic events were identified in two paleo-channels which were labeled as Channels 3 and 4. Wechsler at al. (2014) presented their work from 3 fault crossing trenches (T37, T39, and T44) and 2 fault parallel trenches (T33 and T41a) although many other trenches were cut and logged. This leaves 7.1 m of unresolved slip between ~3000 BCE and the latter part of the 1st millennium BCE - just waiting to be sleuthed. It is also possible that lacustrine seismites could be found south of the site which record more seismic history. Radiocarbon sampling from Wechsler at al. (2014) appears to have been sufficiently dense for historical earthquake work except for the oldest event - Event CH4-E6.

Wechsler et al (2018) extended and refined previous work of Wechsler at al. (2014). They used Petrel software to create a 3D model of the displaced channels and make estimates of offset for a number of seismic events. This, in turn, allows one to make Magnitude Estimates. The Bet Zayda Seismic Events Google Sheet (above) has offset and Estimated Moment Magnitude estimates on the Summary tab. Wechsler et al (2018) also added a new seismic event (CH2-E1) which appears to capture one of the mid 8th century CE earthquakes.

Bet Zayda Plots and Charts

Image Description Notes Source
Map of
Trenches
Fault
Channels
Figure 2 Wechsler at al. (2014)
Trench Log
T45
Figure 3 Wechsler at al. (2014)
Trench Log
T37
Figure 6 Wechsler at al. (2014)
Trench Log
T33
Figure 7 Wechsler at al. (2014)
Trench Log
T39
Figure 8 Wechsler at al. (2014)
Trench T30 Figure 2 Wechsler at al. (2018)
Trenches T30 and T30S Unpublished Thomas Rockwell
Revised Age Model Figure 4 Wechsler at al. (2018)
Revised Age Model
Big
Figure 4 Wechsler at al. (2018)
Age Model Figure 5 Wechsler at al. (2014)
Age Model
Big
Figure 5 Wechsler at al. (2014)
Age Model
really big
Figure 5 Wechsler at al. (2014)
Map of
Trenches
Figure 4 Marco et al (2005)
Fault Parallel
Trenches
Northern Group
T7, T16, T17, T18
Figure 6 Marco et al (2005)
Trench Logs
T10 and T4
Figure 7 Marco et al (2005)
Trench Log
T15
Figure 8 Marco et al (2005)
Age Model Figure 9 Marco et al (2005)
Links to high resolution Trench Photomosaics from Wechsler et al (2014: Figure S1)
Link Caption
Trench T45 a - north wall of T45
b- south wall of T45
Trench T41a c - east wall of T41a, which is a deeper re-exposure of T33
Trench T37 d - north wall of T37
e - south wall of T37
Trench T33 f - east wall of T33 where channel 3 is exposed
Trench T39 g - north wall of T39
h - south wall of T39
Trench T34 i - east wall of T34, where channels 2 and 3 are exposed.
All Trenches Figure S1 [PDF; 42.5 MB]. High resolution photomosaic logs of trench walls. 14C sample dates in the log are not calibrated (years BP). For trench locations, see Figure 2c in the main article. Units are numbered and their descriptions appear in Table S1 of the supplementary material:
  1. north wall of T45
  2. south wall of T45
  3. east wall of T41a, which is a deeper re-exposure of T33
  4. north wall of T37
  5. south wall of T37
  6. east wall of T33 where channel 3 is exposed
  7. north wall of T39
  8. south wall of T39
  9. east wall of T34, where channels 2 and 3 are exposed.
Table S1 Unit descriptions for channels 3 and 4.

References
Notes

Tom Rockwell (personal correspondence, 2022) relates the following:

In our 2014 paper, we show a map of the site, which includes our original locator trench - T30 - in which we searched for channels. For Neta's post-doc work, we focused on the northern set of channels, but look at the ages of the southern several channels - they fill in time periods that we didn't investigate. I believe that area is still open for study - was a bit salty for the farmers.

Bet Zeyda Trench T30
T30 Trench Log

from Tom Rockwell (email 30 March 2022)