Bulletin of Volcanology最新文献

Long-term deformation is observed at many volcanoes worldwide, providing valuable insights into sub-volcanic processes. Deformation also informs on volcano flank instability, which presents a major hazard in the event of a complete or partial collapse of the edifice, which may further trigger a tsunami if the volcano is located near the sea. We explore InSAR datasets to investigate surface deformation of 20 potentially hazardous coastal volcanoes in Southeast Asia. We find that over 90% of them exhibit signs of persistent or episodic surface deformation. Most volcanoes experience line-of-sight (LOS) increase with displacement rates spanning a broad range and reaching up to 29 cm/yr at Ruang. These are either steady, or experience distinct acceleration periods, lasting for several months to years following increased volcanic activity measured as the volcanic radiative power (VRP) and reported periods of unrest or eruptions. We attribute the majority of observed deformation to gravity-driven processes and cooling of young surface deposits. Analysis of displacement components shows subsidence for all cases of LOS increase, coupled with varying horizontal displacements showing either (i) convergence, representing inwards displacements of the flanks due to volume loss by gravitational compaction and cooling contraction, (ii) divergence, representing outwards spreading due to instability of the volcano flanks via surficial downslope flank creep or fault sliding or (iii) near-unilateral horizontal displacements across most of the edifice, representing sliding via a deep detachment fault. We suggest that the horizontal component of InSAR deformation on volcanic edifices may be used to quickly assess the dominant deformation patterns. Applying this concept, we identify potential flank instability at four volcanoes (Anak Krakatau, Lewotobi, Sirung and Ulawun), which may pose future collapse hazards. This work offers new insights into the types and rates of volcano flank deformation, demonstrates a direct link between increased volcanic activity levels and deformation rates, and provides an improved comparative basis to other volcanic regions worldwide.

Supplementary information: The online version contains supplementary material available at 10.1007/s00445-025-01915-z.

Volcanic fissure eruptions can produce voluminous gas emissions, posing a risk to local and distal populations and potentially impacting global climate. Quantifying the emission rate and altitude of injection of these emissions allows forecasting of impacts and provides key insights into the magma dynamics driving eruptions. Daily global observations from satellite instruments such as TROPOMI combined with trajectory modelling with PlumeTraj deliver these emission rate and altitude data. Here, we report satellite-derived SO₂ emissions from the 2022 eruption of Mauna Loa, which lasted only 13 days but produced an SO₂ plume that circled the globe, displaying a highly variable emission rate and injection altitude. Three key discoveries were made: we detect precursory SO₂ emissions up to 3 h before the eruption start; peaks in emission rate are correlated with onset and cessation of activity at different fissures; the SO₂ injection altitude was modulated by the available moisture content of the ambient air. We suggest that alignment of the fissure geometry with the wind direction could potentially explain how the initial emissions reached 14 km asl, approaching the tropopause. The total SO₂ measured from this eruption is 600 (± 300) kt. These results demonstrate how satellite measurements can provide new insights into eruptive and degassing mechanisms and highlight that better constraints on the SO₂ emissions from fissure eruptions globally are needed to understand their impact on climate.

Supplementary information: The online version contains supplementary material available at 10.1007/s00445-025-01839-8.

Lateral dike intrusions into rift zones, repeated in temporal sequences, depend on intrinsic and extrinsic factors including pressure build-up where magma accumulates between intrusions, and the local stress regime influenced by tectonic stress and topography. We reexamine these effects by revising a simplified elastic model of rifting by Buck et al. (2006), where topographic gradients and tectonic stress, in addition to magma accumulation, contribute to the driving pressure of dike propagation. Our model (i) introduces a three-section dike geometry, (ii) assumes lateral dike intrusions follow a positive pressure gradient and open in the part of the rift zone where the local maximum of driving pressure occurs, (iii) restricts the amount of dike opening according to tectonic stress stored prior to a rifting episode, and (iv) incorporates magma compressibility to better understand volume change in a magma domain. As successive intrusions redistribute stress, dike opening is favored at different parts along the rift zone. When applied to the 1975-1984 Krafla rifting episode, the model predicts a spatial distribution of dike openings consistent with geophysical observations, with magma flow into the Krafla fissure swarm through an inlet located ~ 2-4 km north of the Krafla caldera center. Inferred magma pressure at the inlet at the initiation of the first dike is ~ 1-10 MPa above lithostatic stress, whereas tectonic stress and topographic effects contributed > 20 MPa to the driving pressure. The failure pressure limit for the first dike is found to be larger than that for later dikes by a factor of 2. The lower failure limit for later dikes and tectonic stress allow magma flow into subsequent dikes when magma pressure at the inlet is below lithostatic. The model is also applied to fit the spatial distribution of dike openings in the beginning of the 2023-2025 Svartsengi rifting episode in SW Iceland. There, topographic effects contribute ~ 2 MPa of driving pressure to the southern propagation of the first dike. Tectonic stress and significant magma buoyancy (up to 9 MPa) enable dike initiations when the overpressure from magma recharge in the domain was below lithostatic. Tectonic stress inhibited eruption from the initial dike of the Svartsengi rifting episode. Our findings demonstrate that tectonic stress and topographic effects are critical factors driving lateral dike propagation, allowing magma flow into dikes or eruptions under low magma pressure, even lower than lithostatic pressure.

Supplementary information: The online version contains supplementary material available at 10.1007/s00445-025-01897-y.

Basaltic lava flows can be highly destructive. Forecasting the future path and/or behavior of an active lava flow is challenging because topography is often poorly constrained and lava has a complex rheology and emplacement history. Preserved lavas are an important source of information which, combined with observations of active flows, underpins conceptual models of lava flow emplacement. However, the value of preserved lavas is limited because pre-eruptive topography and, thus, syn-eruptive lava flow geometry are usually not known. Here, we use tree-mold data to constrain pre-eruptive topography and syn-eruptive lava flow geometry of the July 1974 flow of Kīlauea (USA). Tree molds, which are formed after advancing lava encloses standing trees, preserve the lava inundation height and the final preserved thickness of lava. We used data from 282 tree molds to reconstruct the temporal and spatial evolution of the ~ 2.1 km-long July 1974 flow. The tree mold dataset yields a detailed dynamic picture of staged emplacement, separated by intervals of ponding. In some ponded areas, flow depth during emplacement (~ 5 m) was twice the preserved thickness of the final lava (2-3 m). Drainage of the ponds led to episodic surges in flow advancement, decoupled from fluctuations in vent discharge rate. We infer that the final breakout occurred after the cessation of fountaining. Such complex emplacement histories may be common for pāhoehoe lavas at Kīlauea and elsewhere in situations where the terrain is of variable slope, and/or where lava is temporarily perched and stored.

Supplementary information: The online version contains supplementary material available at 10.1007/s00445-025-01817-0.

In continental rifts, tectonic deformation, magmatic processes, and earthquakes interact dynamically reflecting the crust's complex response to extensional stress and evolving subsurface and surface conditions. Recent seismotectonic activity in the Fentale-Dofen region of the Main Ethiopian Rift was driven by the intrusion of several dykes reaching up to ~ 50 km in length observed using satellite radar interferometry. Over 300 earthquakes with magnitude 4 or greater were reported by international seismic networks and the GNSS site at Addis Ababa moved ~ 20 mm to the west. These and other observations on the ground were used to create a highly simplified hazard map and 75,000 people were evacuated. Although no magmatic eruption occurred, the earthquakes triggered landslides and caused infrastructure damage, especially to buildings and roads. Here we provide a preliminary analysis of the patterns of earthquakes, ground deformation, and surface manifestations from 2024 to 2025, with a focus on the underlying mechanisms contributing to seismic sequences in the area and key unresolved scientific questions. We discuss how scientific evidence was used to inform decision-makers and examine the short- and long-term implications for critical infrastructure and nearby communities. Finally, we emphasize the importance of real-time monitoring, proactive risk management, and the need for continuous observation and improved early warning systems to reduce future seismic and volcanic risks.

Explosive eruptions of VEI ≤ 3 commonly occur with few warning signs. Such eruptions can be magmatic, phreatomagmatic, or phreatic in nature, and they are driven by the catastrophic release of pressurized gas. Our challenge is how to better forecast these eruptions and better understand them with existing and new tools. Here we examine a number of such eruptions, some lethal to humans, which have occurred during the last decade. We first describe key precursory signals that preceded these events, examine whether they developed in a bottom-up or top-down fashion, and compare the different timescales of precursory activity. In an attempt to understand how, when, and where these systems become pressurized, we then outline the different processes and crustal locations leading to the overpressure. We further identify a number of precursory signals that may be generally applicable and exportable to such systems, and we discuss effective means of using thresholds of these precursory signals and eruptive transitions to improve our forecasting abilities. We conclude by outlining three grand challenges for the next decade: (1) complete forecasts of explosive eruptions including when, where, how big, and what type, (2) a full view of subsurface volcano plumbing, and (3) monitoring networks that are comprehensive, similar, and systematic in nature.

Multiple magmas residing in plumbing systems that feed fissure eruptions can physically and chemically interact and mix during storage, transport, and eruption. The extent and success of such mixing ultimately control the physical properties (e.g. density and viscosity) of the magma, the eruptive conditions, and thus the associated hazards. Analogue experimental studies have previously investigated magma interactions in plumbing systems typically with pipe-like or chamber-like geometries (i.e. cylindrical or cuboidal respectively) and immiscible fluids that represent magma mingling. However, these findings are difficult to extrapolate to high aspect ratio geometries typical of dykes that characterise fissure systems. Here, we present results from a high aspect ratio experimental setup to explore magma mixing within dykes. Using an array of miscible fluid pairs, representing magmas of differing composition, we found that flow is initially localised towards the centre of the system and mixing occurs at the interface between the two fluids, spreading laterally out over time. The mixing interface is generally greater, and mixing is more rapid when the starting physical properties of the two fluids are more similar. Furthermore, a dyke-like geometry facilitates mixing to a greater degree relative to a chamber-like system. We explore the implications of the mixing dynamics on diffusive and crystal exchange between magmas, the transport of magmas through the crust, and the evolution of physical and chemical properties of interacting magmas. The mixing ratio trends of our experimental data are similar to near-real time geochemical mixing data from the Kīlauea 2018 eruption, suggesting a future avenue for understanding the complexities of mixing during magma ascent.

Supplementary information: The online version contains supplementary material available at 10.1007/s00445-025-01809-0.

Volcanoes are not randomly located on Earth, neither are volcanologists. We explored the physical distance between volcanologists and volcanoes by considering two categories of volcanoes: all volcanoes with a confirmed eruption in the Holocene and volcanoes that erupted in the past 50 years (1974-2024). We computed the distance between these volcanoes and the affiliation addresses from volcanologists, defined here as authors having published in the main volcanology journals. We then investigated the dependence of this distance on further bibliometric parameters, such as the journal published in or the author position. Affiliations were extracted from articles published since 1980 in four of the main English-speaking volcanology-focused journals in the Scopus database. Around 27% of volcanologists are based within 100 km of a Holocene volcano, compared to 14% of the world population. More than 85% of volcanologists are within 1000 km of a Holocene volcano, but 48% need to travel over 1000 km to visit a volcano that erupted in the past 50 years. We tested whether distance to the nearest volcano correlates with author position. We observed that researchers working nearer volcanoes tend to lead articles with more co-authors, which is robustly supported by statistical tests. We also found that authors in further positions tend to be based nearer recently active volcanoes, though this correlation is less significant. Using keywords to identify each article's studied volcano, we performed single volcano analysis for the 25 most frequently studied volcanoes in the dataset. We observed significant differences in the distance from authors to the target volcano. For instance, we obtained median author-volcano distances of 9 km for Campi Flegrei and 11,735 km for Merapi. Our analyses also permitted a very simplistic estimate of the carbon footprint from fieldwork travel, yielding CO $_2^{}$ equivalent emissions of about 1 ton per travelling author, with an order of magnitude uncertainty. The database presented is very rich and could serve future efforts in science strategy, equality, diversity and inclusivity, outreach, and sustainability.

Supplementary information: The online version contains supplementary material available at 10.1007/s00445-025-01849-6.

Reliable classification of volcano-seismic signals underpins monitoring and eruption forecasting and is an essential tool for advancing understanding of subsurface processes. However, traditional approaches may overlook the inherent uncertainty and variability between expert judgments. We introduce an innovative method that explicitly quantifies inter-expert agreement using the intraclass correlation coefficient (ICC) and incorporates this measure into probabilistic, ICC-informed soft labels, which can be fed into machine learning pipelines. We conducted a global survey involving 89 experts who classified a set of 80 volcano-seismic events from Ruapehu, New Zealand, providing continuous ratings for standard categories: volcano tectonic (VT), hybrid (HYB), long-period (LP), and other (OT). ICC agreement scores revealed that single-rater scores produce poor agreement between experts even for well-established VT and LP classifications. However, reliability significantly improved for these classifications when multiple expert ratings were combined, although, for HYB and OT categories, expert disagreement remained substantial. We developed a soft labelling methodology that weights class probabilities by their respective ICC scores, resulting in a distribution that naturally reflects expert uncertainty. This demonstrates that ICC-informed soft labels could provide a robust alternative to the hard label standard by explicitly capturing classification uncertainty and variability. Our fully probabilistic view has the potential to significantly enhance machine learning model accuracy, robustness, and transferability across volcanic systems and should provide a fundamental shift in how volcano-seismic data are labelled and interpreted within automated monitoring frameworks.

Supplementary information: The online version contains supplementary material available at 10.1007/s00445-025-01875-4.

Objective: To evaluate the efficacy of chondroitin sulfate (CS) and glucosamine (GS), the most relevant drugs of "Symptomatic Slow Acting Drug for Osteoarthritis" (SYSADOA), in the functional and symptomatic improvement of temporomandibular dysfunction. Although, controversy exists regarding their benefit.

Methods: An electronic search was conducted to retrieve randomized controlled clinical trials (RCTs). The risk of bias assessment was evaluated using the Cochrane Collaboration's tool. Data were meta-analyzed with a random effect model whenever possible.

Results: Three RCTs were included. Qualitative results showed a decrease in pain, joint noise, and inflammatory biomarkers in synovial fluid and an improvement in maximum mouth opening without significant adverse effects. Meta-analysis showed a significant increase in maximum mouth opening with the use of CS-GS (p = 0.19). No statistically significant differences were found in pain reduction compared to tramadol.

Conclusion: CS-GS is effective and safe in the symptomatic and functional improvement of patients with TMD.