On Synchronous Supereruptions

Abstract

The Youngest Toba Tuff (YTT) supereruption from Toba Caldera in Sumatra at ca. 74,000 years BP is the largest volcanic event recorded in the Pleistocene. Intriguingly, recent radioisotopic dating of the near antipodal Los Chocoyos (LCY) supereruption from the Atitlán caldera in Guatemala finds an identical age within uncertainties to that of YTT. This opens the question of whether these synchronous supereruptions may be a coincidence or could be a consequence of each other? Using the known eruptive record from the past 2 Myr, we find that the likelihood of having two near antipodal supereruptions (>1,000 km3 tephra volume) within centuries (<400 years), as suggested by volcanic proxies and annual counting layer chronology in the ice core records, is very small (0.086%), requiring a non-random cause and effect. Considering this analysis, we speculate that one potential physical mechanism that could explain the temporal relationship between these supereruptions is that seismic energy released during YTT eruption focused on the antipodal region, where concentrated stresses ultimately promoted the eruption of the perched LCY magma system (or vice versa). This supereruption “double-whammy” may thus be the more compelling source of the significant environmental impacts often attributed individually to the YTT supereruption. Improving the existing age information of YTT and LCY, and a better understanding of caldera collapse events will enable further testing of the hypothesis that synchronous supereruptions do not result by pure chance.

An assessment of potential causal links between deglaciation and eruption rates at arc volcanoes

“…Furthermore, neither the anticipated degree of change to eruption rates and magma compositions nor the expected time lag between ice retreat and volcanic response are outlaid in the framing of studies aiming to test the hypothesis (Figure 1C). As such, statistical tests are not utilized in the way they are for other volcanological studies that examine causality (e.g., Cisneros de León et al, 2022), and time-volumecomposition trends may be explained via complex, multi-staged, or delayed eruption response models (e.g., Rawson et al, 2016). It is therefore unclear to what degree the erupted magma compositions and volumes are expected to diverge from a baseline due to changes in crustal loading from glacial advance and retreat (Edwards et al, 2002).…”

Los Chocoyos supereruption did not trigger millennial scale cooling

“…74.8 ± 1.7 ka (1σ) 6 is significantly younger. This new radioisotopic age raises the possibility of a 'doublet-supereruption', since LCY and another supereruption, the Younger Toba Tuff (YTT) (73.7 ± 0.3 ka (1σ) 7,8 ), would be within dating uncertainty of each other 9,10 . This younger age also coincides with the onset of a Northern Hemisphere cold period known as Greenland , where a clear transition to colder temperatures lasting ~2000 years is observed in Greenland ice core δ 18 O temperature reconstruction records, beginning at ~74 ka 11 .…”

Resilience of Snowball Earth to Stochastic Events

“…The ash ejected by the event covered ∼40 million km 2 of Earth's surface at a depth greater than 5 mm (Costa et al., 2014). Toba‐like super‐eruptions are expected to happen 1–2 times per million years (Cisneros de León et al., 2022; Mason et al., 2004). Supervolcanic eruptions have significant global climate effects (e.g., Hansen et al., 1978).…”