The deposits of volcanic debris avalanches (VDADs) from collapsed edifices are chaotic matrix-supported breccias associated with debris flow deposits (Glicken 1986). From a total of 210 volcanoes worldwide (Siebert et al. 1987), a total of 288 VDADs have been identified. These are typically associated with subduction zone arc volcanism. For example, 75% of Andean volcanoes (Francis 1984; Dufresne et al. 2021) exhibit VDADs, while a total of 100 destabilizations have been identified along the Japan arc. Additionally, recurrent destabilizations have also been observed in Kamchatka (Shiveluch volcano, Belousov et al. 1999), and Alaska (Waythomas et al. 2000). Avalanche dam break-out floods and fluvial reworking into coarse debris flows during high intensity rainstorms have significant impacts in the vast areas downstream (Capra and Macías 2002; Keigler et al. 2011). The VDADs and their transformed deposits are potentially important archives. However, new ways of parametrizing VDADs are necessary in order to further our understanding of their processes, especially those related to climate controls and matrix transformation into debris flow. Further sedimentary analysis is needed in order to constrain the subsequent hazardous flows associated with quaternary climate changes (Makris et al. 2020; Dufresne et al. 2021).
Textural and semi-quantitative sedimentological analyses contribute to describing the avalanche lithofacies at different scales. The debris avalanche breccias is mainly overlained by a thick carapace of lava blocks. Jigsaw cracks and inherited clasts are observed in a poorly sorted matrix, which shows a coarse stratification with collisional textures. Polymodal and bimodal grain-size distributions interact during collisional and frictional transport (Pierson et al. 1987; Hungr et al. 1996; Iverson 1997). Block ratios decrease distally t with an increasing matrix. This is related to dynamic fragmentation and granular segregation with dilation (Capra and Macías 2002; Clavero et al. 2002; Davies and Mc Savenney 2009; Roverato et al. 2014). Basal fragmentation and comminution contribute to a low basal shear resistance (Caballero and Capra 2011; Bernard and van Wyk de Vries 2017). Clay-rich and hydrothermally altered material can affect the spreading of an avalanche (Glicken 1986): cohesive avalanche deposits (> 3% of silt and clay) are differentiated from non-cohesive massive deposits (< 3% silt and clay). The avalanche flows may be transformed into debris flows by dewatering or dilution downstream (Scott et al. 1995).
The aim of this investigation is to examine the correlations between the spatio-temporal distribution of the quaternary VDADs, the associated volcanic complex, and climate change. For example the Andes have a dry climate, and numerous avalanches have been linked to distinct deposits. A quantitative sedimentary analysis of published data on quaternary volcanoes worldwide has been conducted to determine if climate-related contraints have been recorded in the quaternary avalanche mass flow.
Geological setting
Successive large collapses have occurred along the volcanic arcs of the Pacific Rim subduction zone and the associated microplate boundaries. Collapses along the Juan de Fuca subduction zone were associated with a water-saturated and hydrothermally transformed matrix. For example, the debris flow deposits resulting from the 1980 Mount Saint Helens destabilization along the Cascade magmatic arc and Mount Shasta in the United States (Glicken 1986; Ui and Glicken 1986) have been distinguished. The 1980 Mount St. Helens rockslide was triggered by magmatic intrusion (Voight et al. 1983; Reid et al. 2010; Walter 2011; Siebert and Reid 2023). The snow-rich avalanche deposits on the glaciers of the Illiamna volcano in south-central Alaska were differentiared (1964, Waythomas et al. 2000).
Along the trans-Mexican volcanic complex (TMVB), a total of 12 post-last Glacial Maximum volcanic collapses have been cataloged, indicating a mean recurrence interval of c. 2698 years, despite the majority of VDADs occurring after the Last Glacial Maximum (22 000–18 000 cal BP). Hybrid avalanche deposits with blocks in a cohesive matrix are formed from reworked and interstratified primary edifice deposits. They are a transition between avalanche breccias and debris-flow deposits (Capra and Macías 2002). Field observations and textural analysis consider the basal liquefaction of the Nevado de Toluca edifice with an upper collisional emplacement, and the eastern flank of the Nevado de Colima with a secondary dam breakout and debris-flow downstream. There have been numerous partial collapses of the Colima volcano followed by magmatic eruptions and debris flowing downstream (Capra and Macias 2002; Capra 2007; Caballero and Capra 2011; Roverato et al. 2011, 2014).
The Central Andean Volcanic Zone (CAVZ) shows recurrent destabilizations of 75% of stratovolcano complexes (Francis 1994), with 29% failing between − 1 Ma-112 ka, and 20% between ~-8-7.5 ka. Only two VDADs, Peteroa and Antuco volcanoes in Chile, were identified during the Greenlandien period (-11.7-8.326 ka, Siebert et al. 1987; Dufresne et al. 2021). Likewise, the Antuco basaltic stratovolcano in Chile (Romero et al. 2022) has also been differentiated from the Toreva blocks within the Chimpa VDADs (Argentina, Bustos et al. 2022), and the Azufral and Chimborazo volcanoes (Moreno et al. 2021; Bustos et al. 2022). The asymmetric Chimborazo volcano in Ecuador exhibits lava blocks and mixed avalanche deposits aligned along fault zones. Additionally, the Cubilche VDAD from the northern Andes is distinguished (Roverato et al. 2018). The horseshoe-shaped amphitheater of Tutupaca volcano and its brecciated lava domes (Fig. 1b) are associated with ridged units exhibiting granular segregation of the associated pyroclastic deposits (Valderrama et al. 2016; Bernard et al. 2022).
Hummocky structures observed behind the front lobe are associated with avalanche transformations, such as the Meager rock-avalanche deposits in British Columbia (Fig. 1c; Bernard 2020). For example in the Arequipa basin in Peru, flash floods and debris flow from El Misti VDADs (-833-112 ka) are observed (Fig. 1d; Bernard et al. 2017). The study additionally examined 18 VDADs from the Shiveluch volcano in Kamchatka (Belousov et al. 1999), and 8 mass flow deposits from the Taranaki volcano in New Zealand (Roverato et al. 2014), with a mean recurrence rate of 10,000 years. The variability and, in many cases, unknown causes of edifice failure in the past are serious challenges to any attempt to correlate the increased frequency of debris avalanche occurrences with climatic changes at a range of scales.
Using selected examples, the lithostratigraphic sections of different avalanche units are compared (Figs. 2 and 3), such as the Socompa VDADs in Chile (-7 ka, from van Wyk d Vries et al. 2001, Grosse et al. 2022), the Tutupaca ridges in Peru (Bernard et al. 2022), the Nevado de Colima VDADs in TMVB (-18.5-4.3 ka from Capra and Macias 2002), and the Illiamna VDADs in Alaska (1964, from Waythomas et al. 2000). From the collapsed scar to the distal zone, the internal structures and textural variations are considered in the matrix transformation into debris flow.
From the collapsed scar of the Socompa volcano in Chile (Fig. 2a, Grosse et al. 2022), lava dome breccias have been observed along the sheared basal contact, stretched pumices in the proximal Toreva blocks, and ductile deformations of ignimbrite along the hummocky structures in the median zone. Interstratified pyroclastic units are thrust along the proximal Toreva blocks. The faulted ignimbrite has been extruded in the distal zone. Avalanche units from the lava dome collapse (Fig. 2b) show lava breccias overlaid by pyroclastic deposits (Tutupaca in Peru and Socompa in Chile). The channelized avalanche deposits are covered by reworked matrix breccias transformed into debris flow deposits at Nevado de Colima in the TMVB, and at Illiamna in Alaska (Fig. 2c). In addition, interstratified soils and alluvial deposits are observed. At different scales, different avalanche lithofacies along structural units have been repertoried (Table 1).