Research Article The geology of the 2nd century A.D. Amphitheater Area of Catania, Italy: Historical Eruptions Affecting the Urban District Stefano Branca, 1, * Maria Grazia Branciforti, 2 Antonio Fernando Chiavetta, 2 and Rosa Anna Corsaro 1 1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, Catania, Italy 2 Regione Siciliana, Assessorato dei Beni Culturali e dell’Identit ` a Siciliana, Museo Regionale Catania, Italy Correspondence * Corresponding author: E-mail: stefano.branca@ingv.it Received 16 January 2015 Revised 9 April 2015 Accepted 9 April 2015 Scientific editing by Jamie Woodward Published online in Wiley Online Library (wileyonlinelibrary.com). doi 10.1002/gea.21534 The amphitheater of Catania is one of the main architectural structures built during Roman domination of the town. It was constructed in two successive phases between the 1st and 2nd centuries A.D. and fell into disuse from the second half of the 4th century. Detailed geological and petrographic investi- gations allow better geomorphological reconstruction of the area where the monument was built. In particular, the western and eastern portions of the amphitheater are built on prehistoric lava flows, named Barriera del Bosco and Larmisi, respectively. We infer that the choice of site to build the monu- ment was highly influenced by the morphological setting of the area. In fact, the location at the contact between two lava flow fields facilitated excavation and removal of rocks due to the incoherence of the scoriaceous lateral border of the lava flows. Integrating both archaeological and geological data has re- vealed that a large number of Neolithic, Greek, and Roman sites are located in the lava fields of Barriera del Bosco and Larmisi within the present urban district of Catania, indicating that during its long history the city was directly impacted by only one lava flow, namely in A.D. 1669. C  2015 Wiley Periodi- cals, Inc. INTRODUCTION According to Thucydides, the old city of Catania was founded in 729/728 B.C. as a Greek colony, named Kat ´ an¯ e, of Chalcidic origin in the southernmost coastal sector of Mt. Etna in eastern Sicily (Privitera, 2010). Mt. Etna is one of the most active basaltic volcanoes in the world and has profoundly influenced human activity and the urbanization of its flanks over the last 2700 years (Figure 1). The main eruptive events have been histori- cally documented since the beginning of the Greek col- onization (Tanguy, 1981; Guidoboni et al., 2014). The earliest attempt to correlate historical accounts with in- dividual lava flows on the volcano slopes was performed during the first half of 19th century by Sartorius von Waltershausen (1843–1861), who compiled the earliest geological map of Etna. In particular, the author dated the mapped lava flows by reference to the historical sources available since the medieval age. Later, Sciuto Patti (1872) made a detailed geological map of the city of Catania and surroundings. The oldest historical lava flows of the Roman age, named Carvana and Cifali, recognized by Sciuto Patti (1872) were attributed to erup- tive events in 122 B.C. and A.D. 253, respectively. In par- ticular, the map shows that the Cifali lava flow impacted and destroyed a limited portion of the northwestern sec- tor of the Roman amphitheater of Catania, although no historical sources reported this episode (Tanguy, 1981; Guidoboni et al., 2014). In the geological cartography of the 20th century, Romano et al. (1979) proposed a dif- ferent reconstruction for the same area, suggesting that no historical lava flows reached the Roman amphitheater of Catania that sits mainly on sedimentary basement. In the geological map of Romano et al. (1979), the source of the 122 B.C. event was attributed to a lava flow close to the village of S. Agata Li Battiati, and the source of the A.D. 252/253 event was assigned to a lava flow located in the northwestern periphery of Catania, up to the old Cifali neighborhood, today renamed Cibali. The bound- aries of the A.D. 252/253 lava flow were entirely modi- fied in the geological map of Romano and Sturiale (1981), where this lava formed the coastal sector of the city named Larmisi (Figure 2). In addition, the authors con- firmed that no historical lava flows reached the Roman amphitheater. Recently, Monaco et al. (2000) drafted a detailed geological map of the city of Catania, attributing Geoarchaeology: An International Journal 31 (2016) 3–16 Copyright C  2015 Wiley Periodicals, Inc. 3