Kazzab Trench

Master Seismic Events Table

Charts, Plots, Maps, Images, etc.
Site location

Yammouneh basin Figure 4

Maps of the Yammouneh basin.

  1. Quaternary geology of the basin.
  2. The trench (black rectangle) parallels the channel of the Nahr el-Kazzab stream (thin dashed line) where it crosses the fault (solid white line). A white star marks the location of the main karstic sinkhole (el-Baloua), where the exploratory pit of Figure 5a was excavated.

Daeron et al (2007)

Photos and Maps
  • Fig. DR2 Satellite image of Yammoûneh paleolake from Daëron et al (2005:Supplemental)
The Kazzab trench is located in a paleolake in the Yammouneh basin on the eastern flank of Mount Lebanon. Daëron et al (2005:530) described the location as follows:
The floor of [the] closed pull-apart basin used to be flooded each year by meltwater from karstic resurgences (Besancon, 1968). The lake was artificially dried 70 yr ago, and is now a cultivated plain. Aerial photographs and high-resolution satellite images show that the trace of the active strike-slip fault shortcuts the pull-apart (Fig. DR2). This geometry is clear from changes in soil color and vegetation, as well as inflections or offsets of gullies. Trenching on the east side of the paleolake (Fig. DR2) confirmed the location of the main fault, which cuts a finely stratified, subtabular sequence of lake beds
Daëron et al (2007) identified 10-13 seismic events extending back more than ~12kyr.

Kazzab Trench - Plots, Tables, Trench Logs, etc.

Description Image Source Comments
Tectonic Setting Daeron et al (2007) Figure 1
Postulated Quake Rupture Lengths Daeron et al (2005) Figure 1
Yammouneh Basin Daeron et al (2007) Figure 2
Active fault trace south and
north from the Yammouneh basin.
Daeron et al (2007) Figure 3
Maps of the Yammouneh basin Daeron et al (2007) Figure 4 a&b - Fig. 4b shows trench location
Trench Log of Wall K Daeron et al (2007) Figure 7
Photomosaic of Wall K Daeron et al (2007) Plate 1
Trench Log of Wall G Daeron et al (2007) Figure 8
Stratigraphic log of
the Kazzab sediments
Daeron et al (2007) Figure 6
Stratigraphic log of
the Kazzab sediments - big
Daeron et al (2007) Figure 6
Detailed Stratigraphic Units Daeron et al (2007) Table 3
Examples of
coseismic deformation
Daeron et al (2007) Figure 9
Marl/Clay interface
and calcareous nodules
Daeron et al (2007) Figure 5 b and c
Age Depth Model
"Historic Events"
Daeron et al (2007) Figure 10
Age Depth Model
"Prehistoric Events"
Daeron et al (2007) Figure 11
Events in Kazzab Trench Daeron et al (2007) Table 5
Seismic return intervals Daeron et al (2007) Figure 13
Geological map of Lebanon Daeron (2005) Figure 6

Tentative restoration of the disrupted layers - Daeron (2005)

In order to summarize the events recorded in the Kazzabˆ trench, here is a series of sketches outlining the succession of sedimentation and coseismic deformation that we propose (Daëron, 2005).


1759 vs. 1202 and surface faulting

Photos and Maps

  • Fig. DR1 Fault scarplets on Yammoûneh, Serghaya, and Râchaïya faults from Daëron et al (2005:Supplemental)
  • Fig. 1 Location Map from Daëron et al (2005)
Daëron et al (2005:529-530) discuss how surface faulting evidence may distinguish fault breaks of 1202 vs. 1759
The areas of maximum destruction of the 1202 and November 1759 events overlap, covering an elongated, 150–200-km-long, south southwest–trending zone centered on the Beqaa plain (Fig. 1). Historical accounts of damage thus imply that the events originated on the Yammouneh or Serghaya fault. Macroseismic isoseismal contours tend to be biased toward populated areas: here, the fertile Beqaa Plain. It is therefore impossible to use such data alone to discriminate between the two faults.

The identification and localization of surface faulting associated with the 1202 and 1759 events provides additional clues to determine the faults involved. Archeological and paleoseismic investigation (Ellenblum et al., 1998)1 showed that the 1202 earthquake caused 1.6 m of left-lateral displacement of fortification walls at Vadum Jacob (Fig. 1). A later 0.5 m offset may correspond either to the October 1759 event or to the last large regional event of 1 January 1837 (Ambraseys, 1997). The castle at Vadum Jacob is located south of the junction between the Yammouneh and Rachaıya-Serghaya faults, so the question of which fault took up slip to the north during either event remains open. On the Serghaya fault, in the southern Zebadani valley in Syria Gomez et al. (2001)2 described evidence of recent faulting in the form of a persistent free face 0.5 m high on a scarp cutting soft lacustrine sediments. Trenching in this area, Gomez et al. (2003) exposed a colluvial wedge with modern 14C ages, implying that the latest seismic event postdates A.D. 1650. They interpreted this event to be one of two eighteenth century earthquakes (A.D. 1705 or 1759), but could not discriminate between the two.

Historical sources concerning surface disruption witnessed at the time of the earthquakes are ambiguous. The 1202 Mount Lebanon rock falls3 might hint at stronger shaking on the west side of the Beqaa, hence on the Yammouneh fault, but comparable shaking to the east might have gone unreported [JW: Most translations of most authors just say ]. Ambraseys and Barazangi (1989, p. 4010) mentioned 100-km-long surface ruptures in the Beqaa in November 1759, but stated that the exact location and attitude of (these ruptures) is [sic] not possible to ascertain today. Nevertheless, they inferred the Yammouneh fault to be the most likely candidate. Building on this inference, Ellenblum et al. (1998) referred to Ambraseys and Barazangi (1989) as quoting a description of ground breaks on the Yammouneh fault by the French ambassador in Beirut. Our own investigation of the French sources cited by Ambraseys and Barazangi (1989, p. 4010) yielded only a second-hand account by the French consul in Saida:
One claims that [ . . . ] on the Baalbek side (or possibly: near Baalbek) pulling toward the plain the earth cracked open by more than [~6 m] and that this crack extends for over twenty leagues (~80 km) (Archives Nationales, Paris, B1/1032/1959-60).
The wording suggests that this rupture took place on one side of the Beqaa, and the mention of Baalbek points to the east side, thus to the Serghaya fault.

The inference that the 1759 earthquakes might be due to slip on the Rachaıya-Serghaya fault and the 1202 event on the Yammouneh fault is qualitatively supported by comparing the preservation of scarps and mole tracks along the two faults. Data Repository Figure DR14 [JW: see above] shows the freshest seismic surface breaks we studied in the field. On the east side of the Marj Hıne basin, the Yammouneh fault juxtaposes Cretaceous limestones with Quaternary colluvial limestone fanglomerates. The surface trace of the fault is marked by a classic coseismic scarplet (fault ribbon: e.g., Armijo et al., 1992; Piccardi et al., 1999) that is fairly weathered (Fig. DR1A). North of Serghaya, one strand of the Serghaya fault shows a scarplet of comparable origin, between limestone and limestone colluvium, but with a relatively unaltered surface and lighter color (Fig. DR1B). This scarplet marks the base of a prominent slope break many kilometers long, at places only tens of meters above the valley floor, hence not due to landsliding. On the Rachaıya fault, we found fresh mole tracks in unconsolidated limestone scree (Fig. DR1D), while none are preserved on the Yammouneh fault. The fault ribbon north of Serghaya, which testifies to down-to-the-west normal faulting, fits well the French consul’s description. Such evidence complements that of Gomez et al. (2001) at Zebadani, implying that the latest earthquakes on the Rachaıya-Serghaya fault are younger than on the Yammouneh fault (Tapponnier et al., 2001).

1 JW: see Tel Ateret aka Vadun Jacob

2 JW: see Tekieh Trenches

3 JW: In the English translations of Sibt Ibn al-Jawzi, Abu Shama, and al-Dawardi this is referred to as the mountains of Lebanon or unlocated mountains sometimes with an implication it was near Baalbek as the victims of the landslide or rockfall were described in two accounts as being from Baalbek. Only Ambraseys(2009)'s translation of al-Baghdadi's Letter from Damascus specifies Mount Lebanon while Guidoboni and Comastri (2005)'s translation of the same text refers to the location as mountains of Lebanon. Reference to the original Arabic may resolve this. I have found that some of Ambraseys(2009)'s Arabic translations may be suspect/biased towards his interpretation of the earthquake in question. Baalbek is on the east side of the Beqaa Valley. See Damage and Chronology Reports from Textual Sources -> Locations -> All Locations

2 GSA Data Repository item 2005110, Figures DR1 and DR2 and Table DR1, field photographs of the Yammouneh, Serghaya, and Rachaıya faults, satellite image of Yammouneh paleolake and fault, and accelerator mass spectrometer radiocarbon data, is available online at https://doi.org/10.1130/2005110, or on request from editing@geosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301-9140, USA. JW: These are reproduced below.

Photos, Maps, and Tables

  • Fig. DR1 Fault scarplets on Yammoûneh, Serghaya, and Râchaïya faults from Daëron et al (2005:Supplemental)
  • Fig. DR2 Satellite image of Yammoûneh paleolake from Daëron et al (2005:Supplemental)
  • Table DR3: Radiocarbon dates from Daëron et al (2005:Supplemental)
  • Fig. 1 Location Map from Daëron et al (2005)