Giant rhyolite lava dome formation after 7.3 ka supereruption at Kikai caldera, SW Japan

Abstract

Kikai submarine caldera to the south of the Kyushu Island, SW Japan, collapsed at 7.3 ka during the latest supereruption (>500 km3 of magma) in the Japanese Archipelago. Multi functional research surveys of the T/S Fukae Maru in this caldera, including multi-beam echosounder mapping, remotely operated vehicle observation, multi-channel seismic reflection survey, and rock sampling by dredging and diving, provided lines of evidence for creation of a giant rhyolite lava dome (~32 km3) after the caldera collapse. This dome is still active as water column anomalies accompanied by bubbling from its surface are observed. Chemical characteristics of dome-forming rhyolites akin to those of presently active small volcanic cones are different from those of supereruption. The voluminous post-caldera activity is thus not caused simply by squeezing the remnant of syn-caldera magma but may tap a magma system that has evolved both chemically and physically since the 7.3-ka supereruption.

Isotopic Characteristics of Neogene‐Quaternary Tephra From IODP Site U1438: A Record of Explosive Volcanic Activity in the Kyushu‐Ryukyu Arc

“…Thus, the lack of evidence of certain large-scale Quaternary eruptions is unsurprising. Nevertheless, based on Sr-Nd isotopic composition, depositional age, and overlapping major element compositions of ash shards compared to tephra samples of known rhyolitic eruptions measured by Tsuji et al (2017) and Kimura et al (2015), we are confident that the caldera-forming eruption of Aira (Aira-Tanzawa Tephra, AT), the most prominent tephra marker in the late Pleistocene at circa 29 ka (Machida et al, 2002), and Kikai Volcano (eruption at 77-101 ka, K-Tz; Machida & Arai, 1992, Tatsumi et al, 2018 are well preserved within the tephra record of U1438 (Table 1). The 2-cm-thick ash falls from the Aira and Kikai eruptions are also consistent with the estimated thickness of tephra deposits at this location according to tephra isopach maps of Machida (1999).…”

“…Though individual tephra layers might be correlated through depositional ages, the mineralogy and composition of glass shards is crucial in determining their sources (e.g., Kotaki et al, ; Schindlbeck et al, ; Tsuji et al, ). Nevertheless, constraining the source and extent of ash deposits is an ongoing challenge, as tephra deposits may also derive from currently unknown volcanic sources, such as submerged calderas (e.g., Tatsumi et al, ), volcanic centers covered by products of younger eruptions, or might be related to calderas with unconstrained ages, or whose relations with particular tephra markers are disputed (e.g., Moriwaki et al, ; Nishizawa & Suzuki, ).…”

Stratigraphy and radiocarbon ages of late-Holocene Las Derrumbadas rhyolitic domes and surrounding vents in the Serdán-Oriental basin (Mexico): Implications for archeology, biology, and hazard assessment

“…From the Tertiary Taylor Creek Rhyolite, New Mexico, Duffield et al (1995) report a dome with a volume of 10 km 3 . To our knowledge, the largest (32 km 3 ) single lava dome ever reported is actively being extruded inside the subaquatic Kikai caldera following a large (500 km 3 ) ignimbritic eruption that occurred at 7.3 ka (Tatsumi et al, 2018).…”

Eruptive history of the Late Quaternary Ciomadul (Csomád) volcano, East Carpathians, part II: magma output rates

“…The post-caldera activity at Yellowstone caldera produced even larger-volume individual silicic lava units, such as the 72 ka rhyolitic Pitchstone Plateau of 70 km 3 (Christiansen et al 2007), but these are flows rather than domes. However, rhyolitic domes can also be exceptionally large, such as the 7.3 ka submarine dome at Kikai caldera, Japan, which has a volume of 32 km 3 (Tatsumi et al 2018). Another large dacitic dome, the Nevado del Toluca summit dome complex (Mexico), which formed within the past 50 ky, has a volume of 11 km 3 (Capra et al 2015).…”