Ancient and Medieval Earthquakes in the Area of L'Aquila (Northwestern Abruzzo, Central Italy), A.D. 1-1500: A Critical Revision of the Historical and Archaeological Data

Abstract

This historical seismology study examines and supplements what is currently known from written sources and archaeological literature about the earthquakes that took place in the area of L'Aquila (central Italy), struck by a damaging earthquake on 6 April 2009 (M w 6.3), from the ancient Roman period to the late Middle Ages (first through fifteenth century A.D.). The persistence and magnitude of earthquakes in this area has had a strong bearing on the economy and culture of the communities that resided there, a fact borne out by historical accounts. The goal of this revision is to prompt thinking about earthquakes missing from the hazard estimates as well as on return periods for destructive earthquakes in the area. It presents a critical collation of data previously scattered among historical catalogs and writings. Ten earthquakes are examined for their historical and cultural background with a view to highlighting the existence of written sources and explaining both the quality of the available data and the information shortfall. We also show the limits and uncertainty of the information available, coming as it does from tersely written texts giving patchy coverage. This state of knowledge is due either to sources being lost or in certain centuries not being produced (there is a millennium of "lost" earthquakes) and to the present state of historical and archaeological research in this field. The historical and archaeological data we present are often poor/hard to quantify. Yet they are known and hence pose the problem of how to improve the earthquake catalogs and devise new quantitative approaches to hazard estimation based on multi-disciplinary dialog.

A 667 year record of coseismic and interseismic Coulomb stress changes in central Italy reveals the role of fault interaction in controlling irregular earthquake recurrence intervals

“…Since 9 September 1349 A.D., the day of three well‐document large magnitude earthquakes, the historical catalogue of earthquakes in central Italy, which comprises of macroseismic shaking intensities for damaged towns and villages, is thought to be complete for all earthquakes with M e ≥ 5.8 [ Michetti et al , ; Roberts et al , ; Guidoboni et al , ]. From 1349 A.D., the historical records include 27 large‐magnitude earthquakes; the shaking of individual towns and villages in each of these earthquakes (where I mcs ≥ VIII) is shown in Figure b.…”

Three magnitude 7 earthquakes on a single fault in central Italy in 1400 years, evidenced by new palaeoseismic results

“…As for the lack of historical accounts, this is a normal problem affecting all the medieval earthquakes in Europe, which are rarely and poorly described, or not recorded at all. This is definitely true for this region, where written sources were not produced for the entire EMA, implying a gap in the documentation of earthquakes (Guidoboni et al ., ). Therefore, the Fucino earthquake might have occurred without any surviving written source recording it.…”

Reducing seismic risk by understanding its cultural roots: Inference from an Italian case history

“…Most of the victims were as a result of the total collapse of seven multi-storey concrete-reinforced buildings in via Campo di Fossa 21 n 6 and 6/B, via Cola dell'Amatrice 17, via G. d'Annunzio 24, Via L. Sturzo 3, via Generale F. Rossi 22, via Poggio S. Maria 8 and via XX settembre 79, plus the partial collapse of the university college in the same road. L'Aquila historical seismicity is also very relevant, with foreshock sequences so noticeable that they were recorded by ancient historians before several destructive shocks occurred over 700 years [7,8]. Thus, the high fatal toll may be considered unexpected bearing in mind the long foreshock sequence, the night time of the earthquake and the sparse population distribution.…”