Volcanic collapses and eruptions with VEI >5 (Volcanic Explosivity Index) constitute the large-scale hazards modulating the evolution of volcanic landscapes and climate. The occurrence of these high-magnitude volcanic events makes identifying underlying process controls challenging. From the 288 avalanche deposits of 210 volcanoes worldwide, various categories of debris-avalanche deposits with volumes of many cubic kilometers and long run-outs (up to 100 m/s and 50-100 km; Siebert 1984) are discriminated such as the Bezymianny, Bandai, Shiveluch, and Mount St-Helens volcano case studies (Glicken 1986; Siebert et al. 1987; Belousov et al. 1999, 2007). Quaternary climate changes contribute to large water redistribution, increasing the occurrence of seismicity, volcanism, island volcanic failures and tsunamis hazards during wet and humid climates, such as in the Canary Islands (Keating and Mcguire 2004).
During the glacial-interglacial transition, proxy climate phenomena contribute to increase the occurrence of large volcanic collapses during rapidly changing sea level variations. Slope failures of such types are provoked by deformations induced by magma intrusions, and dome collapses occurred during phreatic eruptions followed by decompression of the collapsed edifices. Bezymianny- and Bandai-type deposits are commonly associated with lahars generated by snow melting, by blast and pyroclastic deposits, and also by dewatering and avalanche transformations (e.g., at Mount St-Helens and Mount Rainier; Major and Voight 1986; Scott et al. 1995). The hybrid avalanche deposits such as the Nevado de Colima avalanche deposits from the trans-Mexican volcanic complex (Capra and Macías 2002), and the middle unit of the Ruapehu deposits (Keigler et al. 2011) in New Zealand are formed of reworked and interstratified primary edifice deposits, and show a transition between avalanche breccias and lahars. These volcanoclastic deposits are generally overlain by coarse debris-flow deposits with reverse grading (Roverato et al. 2014). Successive periods of growth and degradation characterize Mount Taranaki, Shiveluch and El Misti composite volcanoes related to avalanche deposits (Belousov et al. 1999; Zernack et al. 2009; Thouret et al. 2013). Collapses with impact waves and dilation characterize the first stages of the avalanche propagation with transitional flow regime (Scott et al. 1995, 2005). Frictional and collisional transports are differentiated in downstream (Hungr et al. 1996; Iverson 1997; El Zaguán in Mexico, Caballero and Capra 2011). A switch from a frictional to a Voellmy model (McKinnon 2008; Guthrie et al. 2012) is required during avalanche transformations into high velocity debris flows by dilution. Distal impact waves are considered along sheared basal contacts showing pseudotachylite and fault gouge in French Massif Central (Bernard et al. 2017).
The aim of this semi-quantitative study is to consider the relationships between the spatio-temporal distribution and the morphological data of the recurrent debris-avalanche deposits related to the associated volcanic complex and the climate changes. From a semi-quantitative analysis and the published data on Quaternary volcanoes worldwide, 40 volcanic debris avalanche deposits and 61 large eruptions have been examined to determine the climatic and structural controls exerted by the spatio-temporal distributions in the studied parameters of the volcanic debris-avalanche deposits.
Studied volcanic areas
Based on the published data on Quaternary volcanoes worldwide and the Global Volcanism Program databases (Smithsonian Institution, Siebert 1984; Siebert et al. 1987; Mason et al. 2004; Manville 2010), the spatio-temporal distributions of the large volcanic events are repertoried related to volcano-tectonic conditions. Direct correlations with climate and age dating are uncertain (Keating and Mcguire 2004). However, the spatial distributions of the large destabilizations are influenced by tectonic and quaternary climate changes, exhibiting an increase of collapses associated with an enormous redistribution of water during the sea surface warming of the glacial termination (Day et al 2000; Hurlimann et al 2001; Keating and Mcguire 2004). During deglaciation, the addition of snow and water saturation with hydrothermal alteration modified the avalanche mobility with increasing values of the H/L ratios and avalanche volumes. These conditions contributed to matrix transformations into hybrid lithofacies with inherited jigsaw cracks and the debris-flow deposits with dilution downstream into hyperconcentrated flow (Citlaltepetl, Carrasco-Núñez et al. 1993; Illiamna, Waythomas et al. 2000; Mount Rainier, Scott et al. 1995, 2001; Nevado de Colima, Capra and Macías 2002; Roverato et al. 2011, 2014; Ruapehu, Keigler et al. 2011; El Misti, Bernard et al. 2017).
Avalanche structures and flow transformation
Different avalanche units are related to kinematic transitions during flow propagation. A composite scar with striations at the summit (Mount St. Helens, Ontake, Mehl and Schmincke 1999), and several landsliding segments are modified by glacial erosion. Under the collapse scar, transverse blocks or toreva (around ~100 m to several kilometers long) with extensional faults could constitute up to ~30% of the avalanche deposits (Socompa in Chile, Davies et al. 2010). Hummocky structures in the median zone are large cataclased blocks, which are tilted in the mixed matrix, such as Mount Saint Helens in the United States (Glicken 1998), Parinacota and Taapaca in Chile (Clavero et al. 2002, 2004). The lateral levees are differentiated from the longitudinal or transverse ridges (h = 10-30 m, Dufresne and Davies 2009; Andrade and van Wyk de Vries 2010). The frontal lobes thrust the large blocks (Jocotitlán in the TMVB, Siebe et al. 1992) with matrix transformations and dilution into debris-flow deposits (in the French Massif Central, Bernard 2015; Bernard and van Wyk de Vries 2017). The ratio of A/V2/3 is around 1 (Illiamna, Waythomas et al. 2000) compared to other avalanche deposits (~10). Erosion, high-intensity rainstorms, snow melt and submersion are considered with the effects of climate change, which constrain mass flow mobility and the transformation into debris flow. The avalanche reworking in large debris-flow deposits must be considered during the deglaciation and the rainy season.
Collapsed volcanic edifices
Intracaldera break-out floods of volcanic arcs (Alaska, New Zealand, Japan, Kamchatka, Manville 2010) result of combination of volcano-tectonic conditions associated with glacial and deglacial periods during the Quaternary. Recurrent collapses along the magmatic arcs such as the Japanese arc, the Trans-Mexican Volcanic Belt (TMVB), the Cascade magmatic arc, and the Andean volcanic complex have been considered related to the morpho-tectonic characteristics of the avalanche fault zones and the associated deposits related to cyclic evolution of volcanoes and the Quaternary climatic fluctuations.
Since the middle Pleistocene, the partial collapses of Japanese volcanoes associated to tsunamis have produced avalanche deposits and lahars. We differentiated Usu, Komagatake, Myoko, Chokai, Bandai, and Unzen volcanoes along the Japanese arc (Siebert 1984; Capra and Macia 2002). These avalanche deposits are reworked by erosion and successive submersion flows. Yoshida et al. (2012) observed the decreasing sizes of hummocks with the avalanche run-out distance (A = αe(-βD), A: area; D: travel distance; α: intercept coefficient; β: slope coefficient).
The TMVB calco-alkaline continental arc is associated with the subduction of the Cocos and Rivera plates (Bandy et al. 2005). The N-S trending chain recorded a volcanic activity started around -1.7 Ma and migrated southward. The following collapsed edifices are identified, such as Nedavo de Colima, Colima, Popocatépetl, Pico de Orizaba, Jocotitlan, and Nevado de Toluca volcanoes (Siebe et al. 1992; Capra and Macias 2002; Caballero and Capra 2011). These authors dated the volcanic collapses with stratigraphic reconstructions associated with the charcoal found in the interstratified pyroclastic deposits. Capra et al. (2013) show how the climatic variations influence the failure mechanisms occurred just after the Last Glacial Maximum (22 000-18 000 cal BP), with a lower limit of permanent snow around ~3600 m above sea level.
Snow-rich avalanche run-out flows during Holocene are studied on Glaciers of volcanoes in south-central Alaska (Iliamna, Waythomas et al. 2000). The lichens (Rhizocarpon.sp.) give an age of 100-500 yr. BP. The water-saturated collapses of hydrothermally altered volcanic deposits are observed along the Cascade magmatic arc related to subduction of Juan de Fuca plate beneath the North America plate (i.e. Mount Rainier, Mount Saint Helens, Mount Meager; Glicken 1986; Scott et al. 1995, 2005; Vallance and Scott 1997; Friele et al. 2008; Mc Kinnon 2008; Guthrie et al. 2012).
Recurrent volcanic collapses are repertoried along the Andean complex between ~5178 and 6648 m above sea level. These were eroded by the late Pleistocene glaciers. Ticsani avalanche deposits with H/L ~0.13 (Bernard 2008) are differentiated from Tutupaca ridged units with associated pyroclastic deposits (H/L = 0.12, Valderrama et al. 2016; Bernard et al. 2022). For the composite El Misti and Pichu Pichu edifices in Peru (Misti: 833-11 ka; Pichu Pichu <1 Ma on the basis of Nb/La, Th/La and Yb/La ratios, Legendre 1999; Thouret et al. 2001), successive collapses are associated with avalanche transformations into lahars in Arequipa basin (H/L = 0.11-0.24, Bernard et al. 2017).
1. Large volcanic eruptions
The effects of climate changes were exacerbated by the large eruptions generating a winter with incessant rains and floods, such as the Little Ice Age (~1300-1850, Stothers 2000; Miller et al. 2012), and the large eruption of Samalas (1248, Indonesia, Lavigne et al. 2013). The cold periods generate glacial expansion, sea ice, snowstorm, frozen rivers (1608-1814, Lockwood et al. 2017). These fluctuations may also be associated with decreased solar activity (Spörer Minimum between 1400-1550 and Maunder Minimum between 1645-1715, Lockwood et al. 2017), with increased volcanic eruptions (Billy Mitchell in A.D. 1580, Solomon Island; Huaynaputina in A.D. 1600, Southern Peru; Mont Parker in A.D. 1641, Philippines; Long Island between 1651 and 1671 A.D., Papua New Guinea; the 1783 Laki eruption in Western Europe; Mount Tambora in A.D. 1815 and Krakatoa in A.D. 1883, Indonesia; White et al. 1997). Large sulfur-rich explosive eruptions with aerosols were also released into the atmosphere, which contribute to cold climate conditions (Krakatoa in A.D. 1883, Indonesia; White et al. 1997).