The large earthquake on 29 June 1170 (Syria, Lebanon, and central southern Turkey)

Abstract

[1] On 29 June 1170 a large earthquake hit a vast area in the Near Eastern Mediterranean, comprising the present-day territories of western Syria, central southern Turkey, and Lebanon. Although this was one of the strongest seismic events ever to hit Syria, so far no in-depth or specific studies have been available. Furthermore, the seismological literature (from 1979 until 2000) only elaborated a partial summary of it, mainly based solely on Arabic sources. The major effects area was very partial, making the derived seismic parameters unreliable. This earthquake is in actual fact one of the most highly documented events of the medieval Mediterranean. This is due to both the particular historical period in which it had occurred (between the second and the third Crusades) and the presence of the Latin states in the territory of Syria. Some 50 historical sources, written in eight different languages, have been analyzed: Latin (major contributions), Arabic, Syriac, Armenian, Greek, Hebrew, Vulgar French, and Italian. A critical analysis of this extraordinary body of historical information has allowed us to obtain data on the effects of the earthquake at 29 locations, 16 of which were unknown in the previous scientific literature. As regards the seismic dynamics, this study has set itself the question of whether there was just one or more than one strong earthquake. In the former case, the parameters (M e 7.7 ± 0.22, epicenter, and fault length 126.2 km) were calculated. Some hypotheses are outlined concerning the seismogenic zones involved.

Slip rate and locking depth from GPS profiles across the southern Dead Sea Transform

“…However, the rate at which the fault accommodates horizontal displacement is still a matter of debate, as published values vary between 2 and 10 mm/a (Table 1). Although knowledge on historical and archeological seismic history is among the best in the world [ Ambraseys et al , 1994; Ellenblum et al , 1998; Meghraoui et al , 2003; Guidoboni et al , 1994, 2004; Marco et al , 2005; Daëron et al , 2005, 2007; Agnon et al , 2006; Elias et al , 2007], direct and conclusive long‐baseline geodetic measurement of the slip rate has not been published.…”

Seismic evidence for Neogene and active shortening offshore of Lebanon (Shalimar cruise)

“…Available instrumental records, which show a rather low level of recent seismicity on the LFS, are not representative of the long‐term seismicity affecting this area [ Guidoboni et al , 2004]. Large (Ms > 7.0) but relatively infrequent earthquakes are known to have struck Israel, Palestine, Lebanon and Syria in earlier centuries [ Ambraseys and Barazangi , 1989; Khair , 2001].…”

Identification of Source Faults of Large Earthquakes in the Turkey‐Syria Border Region Between 1000 CE and the Present, and Their Relevance for the 2023 Mw 7.8 Pazarcık Earthquake

“…The next significant event back in time in this area is the 1170 earthquake, which is well‐documented, with extensive descriptions by multiple authors (e.g., Ambraseys, 1989, 2004, 2009; Guidoboni, Bernardini, Comastri, & Boschi, 2004; Guidoboni & Comastri, 2005). Guidoboni, Bernardini, Comastri, and Boschi (2004) estimated M w 7.7 ± 0.22 and a fault length of 125 km. Ambraseys (2009) instead estimated M w 7.3 ± 0.3.…”

“…This is compatible with the magnitude estimate of Ambraseys (2009), and reasonably compatible with the damage distribution. The only outlier is the city of Aleppo as reported by Guidoboni, Bernardini, Comastri, and Boschi (2004), but Sbeinati et al. (2010) argue that these authors overestimated the damage in Aleppo based on an erroneous interpretation of the chronicle by Ibn Al Athir.…”

“…This is compatible with the magnitude estimate of Ambraseys (2009), and reasonably compatible with the damage distribution. The only outlier is the city of Aleppo as reported by Guidoboni, Bernardini, Comastri, and Boschi (2004), but Sbeinati et al (2010) argue that these authors overestimated the damage in Aleppo based on an erroneous interpretation of the chronicle by Ibn Al Athir. The argument of Sbeinati et al ( 2010) is reasonable, because the damage distribution is otherwise very unusual, with a single intensity X locality (city of Aleppo) isolated and 200 km away from the main intensity X region (Lebanon-Syria border southwest of Qalaat El Hosn).…”