Appendix 1: Critical review of historically dated eruptions of Etna
Very little can be said about the reference by Diodorus to eruptions that led to the Sicanians fleeing from the Etna region (see Introduction), in c. 1400 B.C. Although he refers unambiguously to lava streams (ρν́ακoς in the text), it is likely that he alludes to activity of his time (Roman epoch), as only strong explosive outbursts were capable to force an entire people to emigrate (Tanguy 1980, 1981). Such cataclysmic eruptions could have produced one or several of the pyroclastic levels dated around 3400 years B.P. by Del Carlo et al. (2004).
Eruptions of 693, 479, 475, 425 B.C. The oldest work quoting the name of Etna is represented by Pindar’s first Pythian ode, that a substantial amount of evidence shows to have been composed around 475 B.C. (Puech 1922). The poet describes the arrival of a lava flow at sea: “He [the giant Typhon] is fast bound by the pillar of the sky, even by snowy Etna, nursing the whole year’s length her dazzling snow. Where out pure springs of unapproachable fire are vomited from the inmost depths: in the daytime the lava streams pour forth a lurid rush of smoke ; but in the darkness a red rolling flame sweeps rocks with uproar to the wide deep sea” (translation in Rodwell 1878). This is probably the same eruption which is quoted in Arundel’s Table, or Parian Marble, as contemporaneous of the Plataea battle in 479 B.C. The date appears further confirmed by the historian Thucydides (III, 116) when alluding to another eruption that occurred in the spring of 425 B.C.: “A stream of fire flowed from Etna, as on former occasions, and destroyed some land of the Catanians ... It is said that fifty years had elapsed since the last flow, there having been three flows in all since the Greeks have inhabited Sicily”. The interval of 50 years might be understood here as approximate, or perhaps the 479 eruption had a rather long duration of 4 years. Alternatively, it remains the possibility that Thucydides was precise enough in writing 50 years (and not 54). In this case, two distinct eruptions should have taken place in 479 and 475 B.C.
In fact, if one accepts the 479–475 B.C. event as a unique phase of activity, then the third and chronologically the first eruption becomes problematic. It is today believed to have occurred in 693 B.C. (Sartorius 1880, and practically all the following authors), on the basis of a very old legend of two pious brothers (the Fratelli Pii) who rescued their aged parents from being overwhelmed by the lava. This act is quoted as an example of filial devotion by many writers from antiquity, the earliest of these being the Athenian Lycurgos in 330 B.C. However, no date is indicated for the eruption, except by Stobaeus (quoting Aelian) who wrote that the event happened during the Olympiad 81, that is about 455 B.C. But this date obviously disagrees with Thucydides’ history, so that Bergk (1873) suspected an error in the manuscript study and corrected it as “Olympiad 21”, actually 695 B.C. because the year of the Olympiad is not specified. Such an interpretation appears highly speculative, all the more so since Aelian and Stobaeus lived in the 3rd and 5th century of the Christian era, which is about a millennium after the event they described.
There is some additional evidence that the 479 B.C. eruption was unusually large and, therefore, the first reported by the Greek writers. This event is linked by the Greek poets Pindar and Aeschylus to the myth of Hephaestos. However, Hephaestos was previously located not in Sicily, but in the Greek island of Lemnos (Guirand 1935; Johnston 2005), where he was then the god of heaven’s fire (lightning). It seems therefore that both his migration to Sicily and his volcanic attribution resulted from Etna’s activity emphasized through the Greek poets of the 4th century B.C.
396 B.C. Diodorus Siculus reports (XIV, 59) that during the war between the Carthaginians and the tyrant of Syracuse (first year of Olympiad 96 and therefore 396 B.C., not 394 as various modern authors indicate) “Imilcar and his army quickly reached Naxos by land [coming from Messina and going southward], but he was then aware that a lava flow from Etna had recently expanded to the sea, so that the terrestrial troops could not follow the seashore together with the vessels because a large part of land had been devastated by what is called lava. For this reason the troops had to walk round Mount Etna”.
140 B.C. According to Julius Obsequens (De prodigiis, quoted by Alessi), “Mount Etna was plentiful of fires, a marvel that went expiated by the sacrifice of forty major victims”. It must be pointed out that victims offered to the gods were sheep, not human beings!
135 B.C. “Etna burned more than usual” (Obsequens), “Mt. Etna belched large fires that flooded as torrents the area located below the place from where flames burst forth, whereas distant regions were devastated through heavy vapours and hot ashfall” (Orosius, V, 6, 2).
126 B.C. “Mt. Etna suffered earthquake and spread fires from its summit over a large area, meantime the sea boiled near the island of Lipari” (Obsequens). These events are also reported by St. Augustine and Orosius, probably using the same source.
122 B.C. “During this summer it is said that Sicily was invaded by such an amount of ash that roofs of the city of Catania were oppressed and overburden, and finally collapsed” (St. Augustine, III, 31). “At this time Mt. Etna burned more than usual and threatened the city of Catania and its outskirts by fiery torrents, so that the roofs of buildings collapsed, being overload and burned by hot ashes” (Orosius, V, 13, 1). The more ancient authors Cicero and Seneca probably allude to the same event when they report that darkness lasted three days and lightning occurred in the volcanic plume. Let us point out that lava flows are indicated by Orosius alone, who wrote more than five centuries after the eruption. Such information, therefore, is of little value (see above a similar discussion regarding Diodorus and the Sicanians).
Most current scientists, following Kieffer (1985), consider the 122 B.C. eruption as a large Plinian outburst (e.g., Coltelli et al. 1998). According to Kieffer, this event created the small caldera of the Cratere del Piano which is today almost entirely buried by the central cone. This view is supported by Strabo’s Geography describing, about a century later, a summit depression 3.8 km in circumference, or 1.2 km in diameter. Seneca said also that at his time (c. A.D. 60), Mt. Etna had a lower elevation than before (letter to Lucilius, n. 51). Moreover, it seems that a long repose period followed the 122 B.C. eruption, as usually occurs after a caldera forming event.
49 B.C. Petronius confirms that an eruption in this year followed a long repose, by saying that “Mt. Etna displayed unusual fires”, and Lucan adds that “the fire split open the slope towards Hesperia” [i.e., westwards], thus indicating a western flank eruption.
44 B.C. Shortly before Julius Caesar was murdered, Etna produced a large eruption (Virgil, Georg.) and heavy ashfall reached as far as Reggio Calabria, 75 km away (Livy). It is worth noting that Virgil, in his poem “Aeneid”, alludes to an “immense harbour” close to Etna. His description, however, was inspired from the Mythology of his time (see Introduction), and does not refer to personal observation.
36 B.C. As indicated in Appianus (Bell. Civ., V, 114), Mt. Etna was shaked by earthquakes and fire was seen from its NW side, very probably linked to a flank eruption.
32 B.C. According to Dion Cassius, an eruption took place this year, but it is not even sure that a lava flow occurred.
At the beginning of the Christian Era, a continuous mild activity within a summit caldera is reported by Strabo (VI, 2, 3–8), although he took his information from Posidinios and this description could be dated some decades earlier. Violent eruptions did occur, however, as attested by Suetonius who wrote (51) that Imperator Caligula was put to flight in Messina because of Etna rumblings, in c. A.D. 38–40.
A.D. 252. This is a famous eruption because it broke out a year after St. Agatha had been martyred in Catania (251): “a year later, almost at her birthday, Mt. Etna suffered a conflagration so that a violent fire which seemed to melt the land and rocks arrived above the city of Catania. Then the crowd of the countrymen fled away and went down to the city. They went to the tomb [of Agatha], took the veil of which it was covered and put this veil against the forthcoming fire: at the same time, the fire was diverted. It began the first day of February calends and stopped on the ninth of them” (Bollandus and Henschenius 1643). This flow was believed to be the “Cibali” flow which invaded the western part of the present Catania (Sciuto Patti 1872), and Sartorius adds that it could have originated from the Monpeloso cinder cone, above the village of Nicolosi (Fig. 1).
1062 (or 1064?). According to Gaufredo Malaterra (in Alessi), a large eruption on the western part of Etna was observed from Troina, at a distance of about 40 km.
1169. On 4 February 1169, a tremendous earthquake struck eastern Sicily, killing some 15,000 people in Catania, but it is unclear whether or not this tectonic event was accompanied by an eruption of Etna. Various reports (see Amico, vol. 2, p. 49–53) make Etna responsible for the catastrophe without definitely quoting an eruption. However, some authors indicate volcanic “fires” and ashfall having caused damage in the country, and Falcando adds that a summit collapse occurred towards Taormina, but there is no allusion to a lava flow directed towards Paterno, as suggested by the CNR map.
At the same time, Pierre de Blois (Petrus Blesensis), the French preceptor of Guglielmo II (king of Sicily from 1167 to 1189), alluded to Etna as a window of the Hell. Dates of possible eruptions, or at less activity, are found in Alessi for the years 1157, 1164, 1194, 1197, 1222, and 1250.
1284–85. A few days before the death of Charles d’Anjou (i.e.,, December 1284 or January 1285), “Mount Etna was violently shaked and from its part regarding towards orient it vomited a terrific fire ... which descended as a torrent on the slope of the mountain and surrounded St. Stephen’s hermitage without damaging it, so that this is today considered as a miracle” (Nicolo Speciale, in Recupero 1815). Such information led Sartorius (1859, 1879) and Romano and Sturiale (1982) to attribute to this event different flows NE of the present Zafferana village.
1329. A violent eruption this year was eye-witnessed by the historian Nicolo Speciale. “On 28 June Mount Etna was violently shaked ... On the eastern flank above the Musarra Rock ... the earth was split open and a violent fire burst forth, together with heavy black fumes and rumbling noises ... this fire cascaded on the slope like a fiery torrent ... On the eastern and southern parts of the mountain the shocks were felt with major violence, near Mascali seashore boats were pulled out by the sea waves ... On 15 July, meanwhile the Musarra fires were still going on, in the lower part regarding the South East, the earth opened near San Giovanni Paparumetta church...” The author then describes the opening of new vents amid forests and “three torrents of fire, two of which advanced for many days towards the region of Aci [presently Acireale] and localities close to the sea ... and the third pointed to the limits of the Catanian territory, where it stopped”. It must be emphasized that no flow is reported to have reached the sea, so that the presumed date of “1329” for the large flow forming the coast at Stazzo (Sartorius 1859, CNR 1979) appears highly questionable (see archeomagnetic results). The eruption ended with strong explosions at the summit Central Crater, making darkness with thunder and causing crop failures, especially around Catania, so that “many men and women died from terror”. Ashfall was noticed as far as the Malta Island.
Similar descriptions are sometimes reported in 1321, 1323, 1328 or 1334, which are obviously misprints (for instance MCCCXXXIIII instead of MCCCXXVIIII). According to Fazello (1558), the 1329 eruption occurred after the mountain was “for many years without burning nor even emitting fume”. Interesting precision is provided by Recupero (p. 28) who found two manuscripts (in Sicilian) that refer to the lower vent of this eruption by the name of “Mt. Russu di San Giovanni Paparometto a lu Fireri”. This can undoubtedly be identified, therefore, as Mt. Rosso near San Giovannello, a church of the Fleri village (Fig. 1).
1333. According to Silvaggio (1542), “similarly it [the volcano] belched with noise fired and burned stones”. This account, added to the misprint quoted above (1334), suggested to Sartorius that a second eruption from Mt. Rosso occurred in these years, an indeed unlikely event because flank cinder cones almost never erupt several times. As the place of the 1333 eruption is unspecified, it could have occurred at the summit Central Crater.
1381. In a manuscript attributed to the monk Simone da Lentini (or his anonymous successor, Muratori 1738), it is reported that “on 6 August 1381 came a fire from Mongibello which burned many olive-trees around the city of Catania”. This led Amico (1741) and most of the subsequent authors to the belief that was then produced the lava flow coming to the sea in the present northern part of Catania, between Ognina and Guardia (Fig. 1). However, Ferrara (1818, p. 80–81) did not agree with this view, rightly observing that such a dreadful fiery stream, so close to the town, could not be alluded to briefly and without apparent emotion. Furthermore, in Fazello’s chronology (1558), this flow is mentioned before the description of the 1169 earthquake.
Whatever the date, the event led to lengthy discussion among the modern authors for determining how and when the “immense harbor” which sheltered Ulysses vessels could have been buried by the lava. This harbor, however, probably never existed when admitting that Homer did not allude to Sicily in his poem (see Introduction).
1408. A flank eruption that year is accurately described by Silvaggio (1542): “On Friday 9 November, towards the 3rd hour of the night [i.e., 3 hours after sunset], Mt. Etna belched a fire, firstly from its main crater, and then from various vents that opened on its lower flank, three miles above the monastery of St. Nicola [near Nicolosi]”. The eruption “caused considerable damage as it devasted many vineyards and houses of the Pedara village. It lasted twelve days, until the 20th of the month”. In another account from Simone da Lentini, “the fire buried the church of Santa Maria del Bosco Inchiuso and lasted 16 days and more”. An anonymous manuscript found by Recupero adds that eruptive activity was preceded by strong earthquakes, and that heavy ashfall occurred as far as Messina and Calabria.
Three large flows between Viagrande and S. Giovanni la Punta (Fig. 1) were attributed to this eruption by Sartorius and all the following authors. However, there is no indication that Viagrande, which already existed at the time, was reached nor even threatened.
1444. In this year, a lava flow was produced towards Catania and, according to Fazello (1558) and Filoteo (1590), the summit Central Crater (thereafter CC) collapsed. We point out that these authors do not allude to the 1408 eruption and, conversely, nothing is reported in 1444 by Silvaggio, who nevertheless indicates two minor events in 1446 and 1447. It may be questioned, therefore, whether or not the 1444 eruption was confused with the 1408 one, so that we checked the existence in Palermo of a manuscript quoted by Fazello, and which is attributed to the bishop Ranzano (S. Scalia, pers. comm.). It is written here: “in the year XLIIII plus MCCCC, when I was 16 years old”, the lava was diverted by St. Agatha’s veil, and then continued for another 20 days. The flow itself, however, is not precisely located.
In the years 1470, 1533, and 1535, eruptions were sometimes reported that were obviously coming from misinterpretations (see Tanguy 1981, p. 596). Instead, it seems that the volcano was rather calm for almost a century, except for the usual mild activity at the summit.
1536. After Mt. Etna had been “for many years without smoke or fire” (Fazello), a large eruption took place on 22 March 1536, which may be summarized as follows: 1) violent fire fountaining at the CC, with lava overflows to the NW and the NE, leading to destructive lahars; 2) opening of three new vents “in the middle of the Schiena dell’Asino close to the Castellacci, one towards Catania, another above the monastery of San Lio del Bosco, and another towards Adrano, above Mt. Minardo, and this later was buried by the 1763 flow” (Recupero, p. 41); 3) opening of a lower fissure SE of Mt. Vetore. This lower flow is the only one accurately located because it overwhelmed the monastery of San Leo. The flank eruption probably ended on 8 April with strong explosions from the CC, which subsequently remained in magmatic activity: “for all the year round flames were seen at the summit, and from time to time extended beyond the crater terrace” (Silvaggio).
1537. The CC activity increased in early May with rumblings. On the 10th (or 11–12?) began a new flank eruption just above the lower 1536 fissure (“Grotte di Paterno” and “Montenegro”, today Mt. Nero del Bosco, at 1700 m elevation below the Sapienza refuge). The 1537 flow was “much longer than that of the preceding year” and traveled for about 15 km, reaching the village of Torre del Grifo near Mascalucia (Fig. 1).
No flank eruption is reported on the NW side in the years 1536–1537, so that the date of “1536” for the large and composite flow reaching the foot of the mountain to the west of Randazzo (CNR 1979) is highly questionable. Possibly there is a confusion with the summit overflows mentioned at the beginning of the eruption, which were unable, however, to reach the lower region.
1566. In November–December of this year, various vents opened on the northern flank “above Mt. Collabasso”, and “a lava flow ran to the chesnuts of Iannazzo” close to the Alcantara River (Recupero, p. 46). A detailed contemporaneous account (Conti 1581) describes five explosive vents above Randazzo and three lava flows, one of which was directed towards Linguaglossa. However, contrary to what is said by Sartorius and the following authors, there is no indication that this small town was reached by the lava.
1578–1580. One or several eruptions occurred these years, apparently towards the SE flank, but no precise location is given. Two different flows dated “1595” on the SW flank in Sartorius’atlas of Etna (1848–1859) do not correspond to any mentioned eruption, not even by Sartorius himself in his 1880 compilation (see discussion in Tanguy 1981; Tanguy et al. 2003).
From 1603 onwards, the eruptions are better described and their location generally do not pose problems (Table 2), however with several exceptions. Thus, the 1610 flows on the SW flank (Carrera 1636) are today reported as 1607 on the geological maps, because they are confused with another eruption taking place that year, but on the northwest side. The long-lived 1614–24 lava effusion on the northern flank produced many advanced flows that were poorly located, and some of them were confused with the 1566 flow (see Fig. 1 and section “Discussion”). Similar misconceptions occurred for the 1643 vents and the 1646–47 flows. In addition to the large 1651 eruption that devastated Bronte on the western foot of the mountain, another flow to the east was mistakenly identified as the “Scorciavacca” flow by Chaix (1892), and unfortunately by all the following authors. In fact, it is specified that the 1651 east flow “took the way between Mascali and Fondo Macchia, descending into the valley of Macchia” (Recupero, p. 60), this being today the “Cavagrande” above the Macchia village, more than 5 km distant from Scorciavacca.
Appendix 2: Location and chemical analyses of samples used for petrochemistry and Ra-Th studies (XRF analyses by CRPG, Nancy, France; Th values taken from Tables 5 and 6)
027, presumed 1408 flow in contrada Ràgala, upslope Nicolosi and Pedara villages on the SSE flank of Mount Etna (SSE, ≈750 m elevation, 37°37′30″N–15°02′30″E)
050, presumed 812 or 1169 flow of Mt. Sona at Sciara Galifi, east of Ragalna (SSW, 800 m, 37°38′–14°57′)
090, presumed 252 flow at Cibali, NW circonvallazione of Catania (SSE, 100 m, 37°31′30″–15°04′15″)
232, large bomb from Mt. Lepre cinder cone on the western flank (W, 1500 m, 37°45′30″–14°55′10″)
333, flow overlain by the presumed 1408 flow, north of S. Giovanni La Punta (SE, 350 m, 37°35′–15°05′)
471, presumed 1329 flow at Linera village (SE, 300 m, 37°40′–15°08′)
535, flow about 400 m north of Trecastagni center (SE, 550 m, 37°37′30″–15°05′)
814, presumed 1284 flow in contrada Ballo, northern Zafferana (E, 600 m, 37°42′–15°06′30″)
1132, presumed 1381 flow east of Gravina village (SSE, 350 m, 37°34′–15°04′)
1146, large lava field of La Nave in contrada Santa Venera (NW, 800 m, 37°51′–14°50′)
1193, presumed 812 or 1169 flow from Mt. Sona at its front near Paterno (SSW, 300 m, 37°35′–14°54′)
1199, recent lava flow from Mt. Arso SW near its front S of S.M. Licodia (SSW, 400 m, 37°36′–14°54′)
1408-1, presumed 1408 flow just above Pedara (SSE, 680 m, 37°37′30″–15°03′30″)
1536-23, 1536 flow west of Mt. San Leo (SSW, 1,075 m, 37°39′30″–14°58′30″)
1610-140, 1610 flow upslope Adrano (SW, 1,000 m, 37°42′–14°53′)
1614-1, 1614-24 flow east of Mt. Spagnolo, northern flank (N, 1200 m, 37°50′–14°58′)
1906, presumed 693 B.C. flow in southern Catania, viale della Regione (SSE, 30 m, 37°30′–15°04′15″)
2027, presumed 1595 lower flow west of Mt. Gallo (WSW, 1,430 m, 37°43′30″–14°54′30″)
2042, presumed 1595 upper flow from the east of Mt. Gallo (WSW, 1,360 m, 37°43′–14°54′30″)
2052, presumed 1536 flow west of Randazzo (NW, 900 m, 37°51′–14°55′)
2149, presumed 1566 flow above Linguaglossa (NE, 750 m, 37°50′–15°06′30″)
2154, small lava flow downslope Mt. Ciacca, presumed 12th century (S, 1,450 m, 37°41′–14°59′)
2155, presumed 1537 flow below Sapienza refuge and “Funivia” cable-car station (S, 1,900 m, 37°42′–15°00′)
2197, lava spatters from Mt. Serra Pizzuta Calvarina (SSE, 1,700 m, 37°41′30″–15°01′30″)
2249, 4110, presumed 1284 flow above Monacella, north of S. Venerina (E, 500 m, 37°42′–15°08′)
2257, presumed 1651 Scorciavacca flow on the lower east flank (E, 840 m, 37°47′–15°08′)
2601, presumed 1408 flow overlain by 027 in contrada Ràgala (SSE, 800 m, 37°37′45″–15°02′45″)
3516, lava spatter from Mt. Arso SE above Pedara (SSE, 950 m, 37°38′45″–15°02′30″)
3645, geologically recent flow at sea below Santa Tecla village (SE, 5 m, 37°38′–15°10′30″)
3672, presumed 1284 flow, 1 km north of Zafferana church (E, 600 m, 37°42′15″–15°06′45″)
3790, presumed 425 B.C. flow at sea, via Rotolo, Catania (SSE, 10 m, 37°31′30″–15°07′)
3843, lava spatter from Mt. Gorna cinder cone on SE flank, presumed 394 B.C. (SE, 780 m, 37°39′–15°04′30″)
3861, geologically recent flow at sea near Cannizzaro (SSE, 10 m, 37°32′–15°07′30″)
3871, presumed 1408 flow north of S. Giovanni La Punta, sciara Pulea (SE, 350 m, 37°35′–15°05′)
3894, geologically recent flow, eastern circonvallazione of Catania (SSE, 50 m, 37°32′–15°06′)
3966, geologically recent flow of Castello del Greco, NE of Santa Tecla (SE, 5 m, 37°38′30″–15°11′)
3985, geologically recent flow in Contrada Verzella, lower north flank (N, 600 m, 37°53′–15°03′)
4048, presumed 394 B.C. flow south of Santa Maria la Stella, lower SE flank (SE, 300 m, 37°36′30″–15°08′)
4074, presumed 1408 flow between Trecastagni and Monte Serra (SE, 490 m, 37°37′–15°05′30″)
4102, presumed 252 flow at southern base of Monte Peloso (or Monpeloso, SSE, 800 m, 37°38′–15°02′)
4120, geologically recent flow overlain by the pseudo 1381 flow SE of Gravina (SSE, 300 m, 37°30′–15°04′)
4144, presumed 1444 flow east of Tre Monti above Trecastagni, lower SE flank (SE, 680 m, 37°38′–15°04′)
4314, presumed 1284 flow west of Dagala village (E, 350 m, 37°42′–15°08′15″)
4323, pyroclastic deposit on SE border of Mt. Ilice (SE, 830 m, 37°39′45–15°05′)
5912, geologically recent flow from Mt. Solfizio (SE, 1700 m, 37°42′–15°02′)
5915, presumed 1329 flow at vent, SE base of Mt. Ilice (SE, 700 m, 37°39′30″–15°05′)
6122, presumed 122 B.C. flow at Piazza Gioeni, northern Catania (SSE, 90 m 37°31′30″–15°05′30″)