Cinder cone growth modeled after Northeast Crater, Mount Etna, Sicily

Abstract

Northeast crater is a pyroclastic cone near the summit of Mount Etna, built to its present volume (1 X 108 m s) by nearly constant strombolian activity since its birth in 1911. Detailed analysis of one typical photograph of a June 1969 eruption indicates that particles exit with a median velocity of about 51 m/s at angles distributed nearly uniformly between 70 ø and vertical. Ejecta consists of ash to 1-m bombs. Physical properties of ejecta include median bomb density, 1.53 g/cmS; particle size of ash found locally on the cone, 150 •t; median size of bombs constituting the cone, 15 cm; sphericity of bombs, 0.78; and surface roughness of bombs, approximately 0.05. Ballistic analysis using these data and including effects of atmospheric drag shows that cinder cone morphology can be predicted by a quantitative model that is in excellent agreement with observed cone features. Cone shape or profile, rim location, limit of continuous ejecta, the ballistic limit (maximum range of ejected fragments), and the size and location of talus slopes are uniquely determined by fragment exit conditions and ballistics. The model suggests that cinder cones grow through four distinct stages: (1) simple cone, with ma.ntle bedding and a low rounded rim, (2) onset of an exterior talus slope, (3) destruction of the original rounded rim by backward migration of the talus, and (4) outward growth of the talus slope beyond the ballistic limit. In the lunar exterior ballistic environment, cinder cones (if they erupted at conditions qualitatively similar to Etna's Northeast crater) should form tuff rings with low, barely discernible rims. Small dark halo craters and dark mantling deposits observed on the moon (such as those near the Apollo 17 site) may be lunar equivalents of normal terrestrial cinder cones. Clusters of such lunar cones might form continuous blankets rather than groups of discrete cones as they do on the earth. Martian cones, formed under the same conditions, would be more like lunar cones than terrestrial ones. This paper presents results of a study of the mode of growth of cinder cones. It focuses on structure, physical properties of ejecta, ballistics, and growth of Northeast crater, a young pyroclastic cone that originated in 1911 near the summit of Mount Etna, Sicily. We describe the cone and the physical properties of the ejecta and relate these properties to the ballistics of the ejecta revealed by an analysis of a photograph taken of Northeast crater in a typical state of eruption in June 1969. From the eruption photography we obtain statistics on ejection velocity and ejection angle for the ejected particles. We use these data to discuss two problems: (1) the mode of growth of Northeast crater and of cinder cones in general and (2) the structure and surface morphology of cinder cones such as Northeast crater on the surface of Mars and the moon, if they were formed under similar eruption conditions. Both problems are approached by exploring the distribution of ejecta and the growth of cones by repeated similar erupti...

Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review

“…The "simple" scoria cone is characterized by a conical structure with a bowl-shaped crater at the top [95]. The scoria cone growth largely invokes models of emplacement and accumulation of pyroclasts through ballistic transportation (no-drag) [96]. The majority of the scoria cone growth models operate with the transportation and accumulation of few cm to few dm sized (scoria or cinder) pyroclastic fragments [95,96] that behave in a granular fashion after deposition [97,98].…”

Topographic Maps of Mount Etna’s Summit Craters, updated to December 2015

“…Etna: (1) the Voragine (VOR), or Chasm, earlier called Central Crater (CC), is the oldest, and has been observed at least since 1858 (Behncke, Neri, & Sturiale, 2004;Lyell, 1858); (2) the NE-Crater (NEC) is a cinder cone that built up from 1911 (McGetchin et al, 1974); (3) the Bocca Nuova (BN) started as a pit crater next to VOR in 1968, and collapsed in 1970 to form a large depression, now joined to VOR (Calvari et al, 1995;Chester, Duncan, Guest, & Kilburn, 1985;Giammanco, Sims, & Neri, 2007;Slatcher et al, 2015), and (4) the SE-Crater (SEC), which formed during the 1971 eruption (Behncke et al, 2006;Calvari, Coltelli, Muller, Pompilio, & Scribano, 1994;Guest, 1973), and has been the most active summit crater over recent decades (Behncke et al, 2006;Bonaccorso & Calvari, 2013;Calvari et al, 2011). Finally, the New SE-Crater (NSEC) (the fifth and youngest summit crater) has formed at the eastern base of the SEC, starting from a little pit crater that opened in late 2007 (Acocella et al, 2016;Behncke et al, 2016;Del Negro et al, 2013).…”

“…Etna is among the world's most active volcanoes ( Figure 1), with almost continuous eruptive activity from the four summit craters Falsaperla & Neri, 2015). Its uppermost region is therefore continuously changing Bisson, Spinetti, Neri, & Bonforte, 2016;Giammanco et al, 2016;McGetchin, Settle, & Chouet, 1974;Murray, 1976Murray, , 1980aNeri et al, 2008;Slatcher, James, Calvari, Ganci, & Browning, 2015), with new vents appearing suddenly and becoming wider and deeper (Calvari, Muller, & Scribano, 1995;Murray, 1980b), and cinder cones building up rapidly owing to powerful explosive activity (Behncke, Neri, Pecora, & Zanon, 2006Calvari & Pinkerton, 2004;McGetchin et al, 1974). This means that the available maps of the summit zone soon become dated in accurately representing its morphology.…”

Geosite of a steep lava spatter cone of the 1256 AD, Al Madinah eruption, Kingdom of Saudi Arabia

“…2B) and its perfect preservation, the site is also scientifically significant. Understanding of scoria cone growth and degradation is a long standing research subject in volcanology [30][31][32][33][34]. In the past decade an increasing number of scientific works have addressed research questions about scoria cone degradation.…”