1138 CE Aleppo Quakes

The first record of this sequence in the scholarly seismological tradition dates back to the first half of the 19th century: in fact, von Hoff (1840) recorded two strong earthquakes in his catalogue at the years 1138 and 1139 in a ill-defined area of the Middle East which included part of Syria (Aleppo), Mesopotamia and Iran. These items of information then passed unaltered into subsequent pre-1900 descriptive catalogues. In the 20th century; Sieberg (1932a) caused the earthquakes to become three, the first being brought forward to September 1137. And the first dating of the month and day started to appear. The tendency to date an earthquake to 1137 still persists in several second-generation (parametric) catalogues, published in more recent times (BenMenahem 1979; Poirier and Taher 1980; al-Hakeem 1988; Khair et al. 2000). Nevertheless, Ben-Menahem himself, in a subsequent paper (Ben-Menahem 1991), records a single large (MI, = 7.4) shock on 12 October 1139. Apart from this change in dating and the addition of previously unstated epicentral coordinates, descriptive data are the same as those contained in Ben-Menahem (1979) for the earthquake of 13 September 1137 (epicentral location to the NE of Aleppo, a shock felt from Mesopotamia to Egypt). Finally, the dating to 1138 reappears in Ambraseys et al. (1994). Apart from these fluctuations in the chronological parameters, we also find other significant differences of interpretation in current catalogues. While, on the one hand, there is a certain agreement in indicating Aleppo as the worst affected location, on the other, there remain considerable uncertainties as to the number of earthquakes and their relative parameters (intensity and/or magnitude); and above all, there is a lack of a clear definition of the area of maximum effects. All these elements contribute to the creation of an even more confusing picture of this seismic sequence, even in the more recent catalogues.

In the main 19th century descriptive catalogues (von Hoff 1840; Mallet 1853) the city of Gansana is mistakenly listed among the locations struck by the earthquake of 1139, probably because of confusion arising between the Syrian events of 1138-1139 and the great earthquake that shook the Caucasian region on 30 September 1139 and destroyed the city (at that time in Persia) of Ganzak (also called Ganza), now Kirovabad in present-day Azerbaijan.

The variety of interpretations of the Syrian earthquakes of 1138-1139 in the seismological tradition mostly derives from the kinds of source used by the individual authors: Ben-Menahem (1979, 1991), Bektur and Alpay (1988), and Khair et al. (2000) base themselves on preceding works and historical catalogues, mostly published during the 20th century, from which they may well have inherited some of their gaps in information and interpretative errors. On the other hand, Poirier and Taher (1980) and al-Hakeem (1988) only use Arabic sources and thus obtain only a partial picture. The first of these catalogues is based on the chronicles of two important 12th century historians (Ibn al-Qalanisi and Ibn al-Athir) but, however authoritative and reliable they may be, they can only provide a partial reconstruction of the event, thus increasing the risk of mistaken parametric interpretations, because the picture obtained from the sources is incomplete. Ambraseys et al. (1994) supply only a partial image of these seismic events, because their catalogue is concerned with the seismicity of Egypt and Arabia and not of Syria.

The oscillations and uncertainties revealed by this excursus into the historical seismological tradition justify the following questions:

1. was it a matter of one or more isolated shocks, as many catalogues seem to suggest, or was it really a seismic sequence?
2. if it was a seismic sequence, when did it start and how long did it last?
3. which area was struck and where was the epicentre?

The study presented here is based on Guidoboni et al. (2004) and aims to answer these questions.

Between October 1138 and June the following year, there was a destructive seismic sequence in the present-day border territories between Turkey and Syria. The most seriously damaged area was in the region of Aleppo (Halab) in north-east Syria and the southern part of the Edessa (now Urfa) area in present-day south-east Turkey. The sources tell of the collapse of a number of places, of which six are explicitly identified: in the Aleppo area: Atharib (Al-Atarib), where there were 600 victims; Azrab, a village near Mt.Quros; Tall Ahmar on the left bank of the Euphrates near Jarabulus, and Zaradna (Sardona for the Latins, Zardana); Shaykh al Hadid; and in the Edessa area: Tall Halid (also called Trihalet).

Perhaps it is worth pointing out that the castles mentioned were very strongly built military structures, all situated on higher ground – a circumstance that could increase shaking effects. Houses collapsed over a wide area at Aleppo, the city walls were damaged, and the citadel as well.

Towers collapsed at Biza`ah, and a church collapsed at Harim, a town in northern Syria, now near the Turkish frontier.

Many of the shocks in the seismic sequence of 1138-1139, especially in October, were strongly felt as far south as Damascus, but no damage was caused there. In particular, three separate shocks were clearly felt at Damascus on 11 October 1138, the day on which the sequence began. The earthquake was not felt at Jerusalem, however. According to the Arab historian Ibn al-Athir (12th-13th century), the earthquakes were also felt in the region of Iraq (Mesopotamia). A total of 80 shocks were felt during the whole seismic sequence.

Near Callinicus (Ar-Raqqah), in the Syrian desert, the earthquake caused cracks and fissures to appear in the ground.

For the sequence of 1138-1139, Syriac and Arabic sources contributed significant information. The new texts, not used in previous studies, are two Syriac sources: Michael the Syrian and the Chronicon ad annum Christi 1234.

The main sources for this earthquake are the contemporary, first-hand reports of Michael the Syrian (1126-1199) and the Arab historian Ibn al-Qalanisi, who personally experienced the earthquake at Damascus. Valuable supplementary information - in some cases it is original — is to be found in the Chronicon ad annum Christi 1234, which dates to the first half of the 13th century, and the chronicle of Ibn al-Adim, an Arab historian from Aleppo (1192-1262). The information provided by Ibn al-Athir is expressed in more general terms.

Michael the Syrian records:

"In the year fourteen hundred and fifty (of the Greeks, 1138-1139), in the month of Tishrin I (= October) ... in the same month there was an earthquake, and the towers were destroyed in Biza`ah and Aleppo".

Michael the Syrian

1138 October 11 — 1139 June

Guidoboni and Comastri (2005)

And he adds important effects upon the natural environment in the Syrian desert:

"And in the desert near Qaliniqos [Callinicus], as forty men were walking on the road, the earth opened and swallowed them all. One survived, for he had turned aside to urinate. The sound of the groaning of the people and their horses rose for a long time. Atharib was also destroyed once again in this earthquake, and the church of Harim collapsed. And also Azrab, a village close to Mount Quros, was torn open in the centre, and when the inhabitants left, it collapsed completely. There was drought in this year until the full moon of Iyyar (= March); so when the rain came, there was a late harvest".

Michael the Syrian

1138 October 11 — 1139 June

Guidoboni and Comastri (2005)

Ibn al-Qalanisi is especially precise when listing the various shocks felt in Damascus between 11 October 1138 and 21 June 1139; and the information he gathered about the Aleppo area, where the worst damage was suffered, was fairly precise, if somewhat brief:

"During the afternoon of Tuesday 4 Safar [11 October], there was a terrible earthquake at Damascus, causing the earth to shake three times. There were repeated further shocks the following Friday at the hour of sunset. During the first third of the night of Monday 19 Safar [27 October], the earthquake returned and the earth shook three times. Praise be to God and the manifest signs of his unfathomable power. There were more shocks during Wednesday night, and yet more in the last quarter of Friday night. Travellers and reliable witnesses have described these shocks in the north [of Syria]. It was at Aleppo and the surrounding area that the earthquake was strongest, causing a large number of houses to collapse, damaging the city walls and producing cracks in the citadel. The populace abandoned their homes in panic, and fled from the city. According to some exaggerated witness accounts, there were a hundred shocks; according to more reliable witnesses, the number of shocks was eighty, but God the Blessed, Lord of the universe, the Almighty, knows what in hidden and what is clear. In the early hours of the morning of Wednesday 21 Shawwal [21 June], there were some terrifying shocks which struck men's hearts with fear. [...] The chronicles record that the citadel of Al-Atharib was taken by 'Imad al-Din Atabik [the Seljukid governor of Mawsil] on Friday 1 Safar [9 October 1138], and they report a strong earthquake in Syria during the night of Friday 8 Safar [15 October]".

Ibn al-Qalanisi

1138 October 11 — 1139 June

Guidoboni and Comastri (2005)

Ibn al-Qalanisi

1138 October 11 — 1139 June

Guidoboni and Comastri (2005)

The Chronicon ad annum Christi 1234 provides briefer information, and also places the earthquake a year earlier, in 1137-1138; but the evidence it offers is still useful, particularly because it helps to establish a southern limit to the felt area by recording that the earthquake was not felt at Jerusalem:

"At this point in the year fourteen hundred and forty-nine (of the Greeks, 1137-1138) there was a severe earthquake; many towns were reduced to ruins, especially in Cilicia and the Syrian territories. The strong fort of Atharib was thrown down to earth as if it had never existed. But (the vibrations) did not reach Jerusalem".

Chronicon ad annum Christi 1234

1138 October 11 — 1139 June

Guidoboni and Comastri (2005)

Ibn al-'Adim, an Arab historian who was born at Aleppo in 1192 and died in 1262, provides a detailed account of the seismic sequence of 1138-1139, including the names of some affected places which are not recorded in the other sources (Shih, Tall 'Ammar, Tall Khalid and Zaradna):

"On Thursday 13 Safar [22 October], there was a violent earthquake, followed by more shocks. The people of Aleppo fled from the city into the countryside. Pieces of stone were thrown out of walls and plunged into the street and people heard deafening rumbling noises. The citadel of Al-Atharib collapsed on top of 600 Muslims; only the governor and a few others survived. Many places were destroyed. Shih [Shaykh al Hadid], Tall 'Ammar, Tall Khalid and Zarradna. The earth was seen to sway, and the trees shook like corn in a sieve. Many houses were destroyed at Aleppo, and the city walls were damaged. Those of the citadel also suffered. [`Imad al-Din] Atabik [al-Zanki], coming from the east, took the city, made his way towards the citadel and proceeded in the direction of Mawsil. The earthquakes continued until the month of Shawwal; it was said that there were 80 shocks".

Ibn al-'Adim

1138 October 11 — 1139 June

Guidoboni and Comastri (2005)

Only very brief information about the earthquake is provided by Ibn al-Athir. He records that:

"There were many terrible earthquakes in the Syrian territories, Mesopotamia and many other provinces; but the most violent were in the Syrian territories, where they lasted for many nights, accompanied by tremendous rumbling and shaking".

Ibn al-Athir

1138 October 11 — 1139 June

Guidoboni and Comastri (2005)

As regards the Latin sources, we feel it is safe to say that the news of these earthquakes had a poor circulation or reception in Crusader areas, although they were partly affected, as well as in the Western Europe. We have to bear in mind that the area was strongly disturbed by troop movements and by local uprisings, as well as by raids to obtain control of the territory: the imperial Byzantine army was positioned at that time on the plain of Antioch and had encamped on the northern part of the River Orontes; and the Byzantine war machines 'bombarded' Antioch for days on end (Runciman 1951-54).

The years in question coincide with the start, in 1137, of Zinki's counterattack against the fortresses of Ba`rin, Al-Ma'arra and Kafar Tab, which led to a rupture with the Franks. And it was Ibn al-Athir himself who referred to those years with these words:

"The populations were reduced to squalor and misery for those places were the theatre of military operations, and so lootings and killings were very much a day-to-day affair".

But even fortuitous contingencies may play a role in the dissemination of news. Practically nothing of interest is to be found in European annals of the 12th and 13th centuries or the Latin texts in the history of the crusades corpus corpus for the history of the Crusades. In particular, William of Tyre, who wrote in the second half of the 12th century, made no mention of these earthquakes, perhaps more attracted by the military events that were taking place. It is likely that some echo of these events may be contained in a record of an earthquake, couched in very general terms, in the Benedictine annals of the abbey of Gottweig (Annales Gotwicenses), in the diocese of Passau (north-eastern Austria).

The text gives the date as the fourth day before the Calends of October (i.e. 28 September) and the location as "in certain places" (in quibusdam locis). So we can not exclude the possibility that not only a local earthquake but also events in far-off lands are being referred to, though without the oral transmission of information offering much detail. This source adds no information to the data contained in the Arabic and Syriac sources.