ICESat-2 Applications for Investigating Emerging Volcanoes

Submarine volcanism in shallow waters (<100 m), particularly in remote settings, is difficult to monitor quantitatively and, in the rare formation of islands, it is challenging to understand the rapid-paced erosion. However, these newly erupted volcanic islands become observable to airborne and/or satellite remote sensing instruments. NASA’s ICESat-2 satellite laser altimeter, combined with visible imagery (optical and microwave), provide a novel method of evaluating the elevation characteristics of newly emerged volcanoes and their subaerial eruption products. Niijima Fukutoku-Okanoba (NFO) is a submarine volcano 1300 km south of Tokyo (Ogasawara Archipelago of Japan) that periodically breaches the ocean surface to create new islands that are subsequently eroded. The recent eruption in August 2021 is a rare opportunity to investigate this island evolution using high-resolution satellite datasets with geodetic-quality ICESat-2 altimetry. Lansdat-8 and Planet imagery provide a qualitative analysis of the exposed volcanic deposits, while ICESat-2 products provide elevation profiles necessary to quantify the physical surface structures. This investigation determines an innovative application for ICESat-2 data in evaluating newly emerged islands and how the combination of satellite remote sensing (visible and lidar) to investigate these short-lived volcanic features can improve our understanding of the volcanic island system in ways not previously possible.

Under the surface: Textural analysis of complex, multi-component Vulcanian bombs produced during the hybrid effusive-explosive phase of the 2011-2012 Cordón Caulle eruption, Chile

<p>The ascent, eruption, and deposition of volcanic pyroclasts is complex, but the resultant rocks have distinctive textural markers that indicate the unseen processes that were operating during a given eruption. These textures can be used to build a picture of the sequence of events and the eruptive environment. Vulcanian eruptions, short-lived, intermittent blasts interpreted as the clearing of a conduit plug, produce ballistic pyroclasts with textures that are directly correlated with the makeup of the plug material. A late phase of the recent eruption of Puyehue-Cordón Caulle (2011-2012, Southern Chile) produced a striking array of, colourful, and texturally diverse Vulcanian bombs. The eruption began on June 4th 2011 with Plinian to Sub-Plinian activity, transitioning to a phase of obsidian lava effusion on June 15th, and then to a hybrid effusive-explosive phase (vulcanian bomb ejection coeval with an effusive obsidian lava flow) in January 2012. Transitions from explosive to effusive activity are often described as singular, definitive, one-way events, at odds with the hybrid effusive-explosive activity seen at Puyehue-Cordón Caulle. Textures in these bombs indicate that the constituent melts have experienced several (possibly countless) episodes of fragmentation, sintering, densification, shearing, and vesiculation within a conduit-scale breccia pack, conceptually equivalent to a conduit-scale tuffisite vein. In all examined bombs, centimetre to micron scale clasts of basaltic-andesite (~SiO2 54-55 wt%) are found, with textures that indicate a magmatic origin. Although volumetrically minor, co-mingling of a hotter, mafic magmatic component has implications for the anomalously hot rhyolite, as well as the onset and longevity of the hybrid eruption phase. Textural and geochemical characteristics of bombs elucidate complex processes in the shallow conduit and vent, advancing the understanding of tuffisite veins and Vulcanian eruption dynamics, which are far from straightforward.</p>

Under the surface: Textural analysis of complex, multi-component Vulcanian bombs produced during the hybrid effusive-explosive phase of the 2011-2012 Cordón Caulle eruption, Chile

<p>The ascent, eruption, and deposition of volcanic pyroclasts is complex, but the resultant rocks have distinctive textural markers that indicate the unseen processes that were operating during a given eruption. These textures can be used to build a picture of the sequence of events and the eruptive environment. Vulcanian eruptions, short-lived, intermittent blasts interpreted as the clearing of a conduit plug, produce ballistic pyroclasts with textures that are directly correlated with the makeup of the plug material. A late phase of the recent eruption of Puyehue-Cordón Caulle (2011-2012, Southern Chile) produced a striking array of, colourful, and texturally diverse Vulcanian bombs. The eruption began on June 4th 2011 with Plinian to Sub-Plinian activity, transitioning to a phase of obsidian lava effusion on June 15th, and then to a hybrid effusive-explosive phase (vulcanian bomb ejection coeval with an effusive obsidian lava flow) in January 2012. Transitions from explosive to effusive activity are often described as singular, definitive, one-way events, at odds with the hybrid effusive-explosive activity seen at Puyehue-Cordón Caulle. Textures in these bombs indicate that the constituent melts have experienced several (possibly countless) episodes of fragmentation, sintering, densification, shearing, and vesiculation within a conduit-scale breccia pack, conceptually equivalent to a conduit-scale tuffisite vein. In all examined bombs, centimetre to micron scale clasts of basaltic-andesite (~SiO2 54-55 wt%) are found, with textures that indicate a magmatic origin. Although volumetrically minor, co-mingling of a hotter, mafic magmatic component has implications for the anomalously hot rhyolite, as well as the onset and longevity of the hybrid eruption phase. Textural and geochemical characteristics of bombs elucidate complex processes in the shallow conduit and vent, advancing the understanding of tuffisite veins and Vulcanian eruption dynamics, which are far from straightforward.</p>

More Sloppy Reasoning about Survival

In my writings on the evidence for postmortem survival. I’ve made no secret of the fact that I consider much of the literature on the subject to be very shabby, usually because the authors are empirically myopic or inferentially-challenged. That is, writers on survival notoriously ignore or treat very superficially relevant areas of research having their own extensive literatures (e.g., on dissociation, savantism, prodigies, gifted under-achievers, and language mastery), and too often they seem unable to formulate valid arguments. In Braude, 2003 I explored these deficiencies in great detail. Here, I’d like simply to comment on a particular class of confusions and a recent eruption of nonsequiturs.

Saved by the Baguette

Volcanoes are an important cause of catastrophic tsunamis, none more so than Santorini (Thera) that erupted with devastating power approximately 1600 BC. This Late Bronze Age eruption generated a tsunami that rampaged throughout the Mediterranean and saw the beginning of the end for the Minoan civilization at the time. In more recent times, the 1883 eruption of Krakatau in Indonesia caused similar mayhem. However, the recent eruption of Krakatau’s child, Anak Krakatau, shows the disturbing ability of volcanoes to rebuild and repeat. In this chapter, these events and several more are charted through their local and distant effects, concluding with a salutary tale about the man in Martinique who was saved by a stolen baguette.

Eruption of Mount Ile Lewotolok on November 29, 2020: A Historical Volcanic and Tectonic Seismicity Assessment

An eruption of volcano is related to the past volcanic and tectonic seismicity. Recently, on November 29, 2020, a 1423 m Mount Ile Lewotolok in Lembata Island has erupted. In here, this paper aimed to assess the volcanic and tectonic seismicity as determinant factor and precursor of recent Mt Ile Lewotolok eruption. The assessment shows that Mt Ile Lewotolok volcanic activities were characterized by both tectonic and deep volcanic seismicity. Since 2010, mean tectonic quake magnitudes of M 4.133 (95%CI:M 3.205-5.062) have occurred at mean depth of 13.500 km (95%CI:8.201-18.799 km) within a distance of 3-4 km from the summit. Tectonic quake has occurred frequently in southwest of Ile Lewotolok and this has contributed to the past eruptions in 2012 and 2017. Recent eruption has been influenced by deep volcanic seismicity rather than local tectonic. Based on November 2020 record, mean of deep volcanic seismicity frequency was 2.190 events/day (95%CI:1.136-3.243 events/day km) that has outnumbered (ttest=2.665, P=0.013) the events of local tectonic quakes (mean 0.621 events/day; 95%CI:0.142-1.099events/day). Prior to the eruption there was significant increase of deep volcanic seismicity (P=0.023) while local tectonic quake was not showing an increasing trend (P=0.764). This result confirms that the deep volcanic seismicity frequency is a precursor that may trigger the eruption and deep volcanic seismicity data can be used as indicator of volcanic activities.

Volcanism in the Longgang Volcanic Field of Northeast China: Insights from eruption history, volcano types, and geochemical characteristics

The Longgang volcanic field (LVF) is a monogenetic volcanic field in China that erupted in the Quaternary, forming more than 100 scoria cones and maars in an area of over 1500 km2. The most recent eruption occurred approximately 1500-1700 years ago. By summarising the results of previous and recent research, this paper reviews the geological background, volcano distribution, eruption history, typical volcanoes, and geochemical characteristics of the LVF. The volcanic activities in the LVF were structurally controlled by near-EW, NW-, and NE-trending faults. An analysis of typical volcanic edifices reveals that at least two eruptive episodes occurred in the Holocene, and most of the maars in the LVF have characteristics of multiple eruptive styles. It is concluded that the eruption types included effusive eruptions, magma explosive eruptions, and phreatomagmatic eruptions. The results of geochemical studies of LVF eruptive products show that most of the rock is trachybasalt and that the magma rarely interacts with crustal rocks. Compared with the previous results for the neighbouring Changbaishan polygenetic volcanic field, the probable origins of their differences in volcanism are discussed.

Analysis of swarm earthquakes around Mt. Agung Bali, Indonesia prior to November 2017 eruption using regional BMKG network

Mt. Agung, located in Karangasem-Bali, Indonesia, had a significant increase of swarm earthquakes from September 2017 until the recent eruption in November 2017. To analyze the seismic swarm and its correlation with the magmatic movement, we worked on the regional seismic data recorded by Agency for Meteorology, Climatology and Geophysics of Indonesia (BMKG) between September 14 to October 20, 2017. P-and S-wave phases of the swarm events had been manually picked. In total, 804 events in the time period of September 14 to October 20, 2017 were successfully determined. To improve the location precision, the double-difference relocation method was performed. We identified most of the events as Volcano-Tectonic type A (VT-A) earthquakes and located between Mt. Batur and Mt. Agung. Those events form a cluster striking in NE-SW direction at a depth between 2 and 20 km. Focal mechanism solutions for selected events below Mt. Agung show a thrust and strike-slip faulting regime. Interestingly, a trend of event propagation toward the summit of Mt. Agung was observed. The frequency of VT-A event occurrences is significantly increased at the later stage of the swarms. We concluded that the increased seismic activity in Mt. Agung was due to the migration of magma from the deep chamber to the shallow reservoir.

Correction to: Recent eruption history inferred from eruption ages of the two latest lava fows using multi-dating at Yokodake Volcano, Japan

An amendment to this paper has been published and can be accessed via the original article.

Recent eruption history inferred from eruption ages of the two latest lava flows using multi-dating at Yokodake Volcano, Japan

Reconstruction of the eruption history of an active volcano is necessary to elucidate its volcanic activity and to assess the probability of its volcanic eruption. Yokodake volcano in central Japan is the only active volcano among the Yatsugatake volcano group. It has effused nine lava flows, most of which have not been dated. For this study, we ascertained the eruption ages of the latest lava (Y9) and second most recent lava (Y8) using radiocarbon (14C), thermoluminescence (TL), and paleomagnetic dating methods. Results revealed the eruption ages of the two lava flows and the recent eruption history of Yokodake volcano. Yokodake volcano effused its Y8 lava flow at ca. 3.4 ka, ejected NYk-2 tephra with explosive eruption at ca. 2.4–2.2 ka, and effused the Y9 lava flow associated with Y9-T tephra at ca. 0.6 ka. Magma eruption rates of Yokodake at 34 ky and 3.4 ky were estimated as about 9 × 10−3 km3/ky and 1 × 10−2 km3/ky, indicating a stable eruption rate maintained during the past 34 ky. This result suggests that Yokodake volcano retains some potential for eruption, although the volcanic activity of the Yatsugatake volcanoes (10−1–10−2 km3/ky) has weakened over time.