Explosive Activity Research Articles

The effects of blood flow restriction training on post activation potentiation and upper limb muscle activation: a meta-analysis.

This meta-analysis aims to systematically evaluate the impact of blood flow restriction training (BFRT) on muscle activation and post-activation potentiation (PAP) in the upper limbs, to provide guidance for upper limb protocols aiming to enhance explosive strength and activation. PubMed, CNKI, Web of Science, and EBSCO databases were queried to identify randomized controlled trials (RCTs) investigating the effects of upper limb BFRT on muscle activation and PAP. Inclusion and exclusion criteria were applied using the Cochrane bias risk tool. Literature quality assessment and statistical analysis were conducted using Revman 5.4 and Stata 17.0 software. Sensitivity analysis and funnel plots were utilized to assess result stability and publication bias. A total of 31 articles involving 484 participants were included in the analysis. Meta-analysis results showed that upper limb BFRT significantly increased muscle iEMG values [SMD = 0.89, 95%CI (0.21, 1.58), p = 0.01]. BFRT had a significant effect on upper limb explosive force [SMD = 0.73, 95%CI (0.41, 1.04), p < 0.00001]. Subgroup analysis based on literature heterogeneity (I 2 = 92%, 80%) showed that exhaustive BFRT significantly decreased upper limb iEMG [SMD = -0.67, 95%CI (-1.25, -0.09), p = 0.01], with exercise modes including maximum output power of bench press [SMD = 1.87, 95%CI (0.22, 3.53), p < 0.0001], exercise intensity of 40%-70% 1RM [SMD = 1.31, 95%CI (0.61, 2.01), p < 0.0001], and pressure intensity of ≥60% AOP [SMD = 0.83, 95%CI (0.43, 1.23), p < 0.0001] reaching maximum effects and statistical significance. Upper limb BFRT can induce muscle activation and PAP. BFRT with 40%-70% 1RM and ≥60% AOP in the upper limbs is more likely to promote PAP. http://inplasy.com, identifier INPLASY202430008.

Gas buffering of magma chamber contraction during persistent explosive activity at Mt. Etna volcano

A sequence of more than 20 short-lasting explosive eruptions took place at Mt. Etna volcano, during a 2-month period in 2021. Here we perform a joint analysis of the gravity decrease and ground deflation that accompanied the sequence of eruptions. Results from this joint analysis are cross-checked against the output of a numerical code providing independent geochemical insight on how the density of the magmatic liquid/gas mixture in the source reservoir varies as a function of the pressure. This cross-analysis provides a framework to explain why (i) the bulk volume reduction sensed by the ground deformation data is much lower than the volume of the erupted products and (ii) the observed gravity changes point to a strong mass decrease, incompatible with a pure mechanism of magma withdrawal. We conclude that pressure-driven gas exsolution and expansion compensated the withdrawal of magma, thus buffering the contraction of the source reservoir and leading to the inferred mass decrease.

ПОЛЕВЫЕ РАБОТЫ НА СЕВЕРНЫХ СКЛОНАХ КРОНОЦКОГО ВУЛКАНА В ИЮЛЕ-АВГУСТЕ 2023 г.

In July-August 2023, field work was carried out on the northern slopes of Kronotsky volcano in the territory of the Kronotsky State Reserve, which is rarely visited by researchers. The aim of our work was to sample lavas that build the volcanic edifice in this sector, and also to search for traces of the volcano’s explosive activity in the Holocene. This report lists and illustrates interesting findings and the main results of the work. In particular, lava flows, dikes and pyroclastic horizons were sampled at altitudes ranging from 780 to 2200 m; several cinder and lava cones were discovered; samples of cognate inclusions and xenoliths were found. In addition, Holocene soil-pyroclastic sections, presumably containing tephra horizons from Kronotsky volcano, were documented in detail and sampled.

Remobilization and eruption of an upper crustal cumulate mush at the Singkut caldera (North Sumatra, Indonesia)

Understanding the conditions and timescales of storage and remobilization of magma bodies in the upper crust is key to interpreting the signals of potential reawakening at active volcanoes. In this paper, we provide the first volcanological and petrochronological characterization of the Singkut caldera, a young volcanic system located in northern Sumatra (Indonesia), in close proximity to Medan, one of the country's most popoluous cities. Singkut formed at ∼44 ka during a VEI 6 explosive eruption that deposited at least ∼26 km3 of tephra (dense rock equivalent, DRE). The cataclysmic eruption was preceded by >200 ky of mostly effusive pre-caldera activity and followed by effusive to mildly explosive post-caldera activity. The lavas and pumices have high crystallinity (up to 62% crystals) with andesitic to dacitic bulk-rock composition and rhyolitic glass. Mineral textures and matrix glass compositions indicate resorption of quartz, plagioclase and zircon. Zircon crystallization ages show a complete overlap with the eruption ages in pre-caldera lavas, while a time gap in zircon crystallization (>50 ky) is identified in the caldera-forming tuff and post-caldera lavas. Ti-in-zircon thermometry shows that the Singkut magma body experienced a temperature increase starting approximately upon eruption of the pre-caldera lavas (∼254 ka). Such thermal perturbation determined progressive melting of mineral phases in the cumulate crystal mush, caused the resorption of the youngest zircon domains before the caldera-forming eruption, and hampered zircon crystallization between the caldera-forming eruption and the effusion of the post-caldera lavas (∼16 ka). Our data demonstrate how cumulate melting processes played a key role in leading the volcanic system towards a caldera-forming eruption and controlled the transitions in eruptive style between the effusive phases and the explosive climactic eruption.

A 6.2 Ma‐Long Record of Major Explosive Eruptions From the NW Pacific Volcanic Arcs Based on the Offshore Tephra Sequences on the Northern Tip of the Emperor Seamount Chain

AbstractWe present a continuous ∼6.2 Ma long record of explosive activity from the Northwest Pacific volcanic arcs based on a composite tephra sequence derived from Ocean Drilling Program Sites 882A and 884B, and core MD01‐2416 on the Detroit Seamount. Geochemical fingerprinting of tephra glass using major and trace element analyses and correlations of tephra layers between the three cores allowed the identification of 119 unique tephras, suggesting eruptions of magnitude (M) of 5.8–7.8. Age estimates for all the identified eruptions were obtained with the help of published and further refined age models for the studied cores, direct 40Ar/39Ar dating of four ash layers, and Bayesian age modeling. The glass compositions vary from low‐ to high‐K2O basaltic andesite to rhyolite and exhibit typical subduction‐related affinity. The majority of the tephras originated from Kamchatka, only a few tephras—from the neighboring Kuril and Aleutian arcs. The glass compositions revealed no temporal trends but made it possible to identify their source volcanic zones in Kamchatka and, in some cases, to determine their source eruptive centers. Our data indicates episodes of explosive activity recorded in the Detroit tephra sequence at ∼6,200, 5,600–5,000, 4,300–3,700 ka, and almost continuous activity since ∼3,000 ka. Within the latter episode, the most active intervals can be identified at 1,700–1,600, 1,150–1,050, and 600–50 ka. Geochemically fingerprinted and dated Detroit tephra sequence form a framework for dating and correlating diverse paleoenvironmental archives across the Northwest Pacific and for studies of geochemical evolution of the adjacent volcanic arcs.

Our fragile future under the cumulative cultural evolution of two technologies

We derive and analyse a model with unusual features characterizing human activities over the long-run. First, human population dynamics draw heavily on consumer–resource modelling in ecology in that humans must consume biological resources to produce new humans. Second, the model also draws heavily from economic growth theory in that humans do not simply consume biological resources; they also produce the resources they consume. Finally, humans use two types of technology. Consumption technology affects the rate at which humans can extract resources. Production technology controls how effectively humans convert labour into new resources. The dynamics of both types of technology are subject to cumulative cultural evolutionary processes that allow both technological progress and regress. The resulting model exhibits a wide range of dynamical regimes. That said, the system is routinely sensitive to initial conditions, with wildly different outcomes given the same parameter values. Moreover, the system exhibits a basic fragility in the sense that human activities often lead to the endogenous extinction of the human species. This can happen gently, or it can follow periods of explosive human activity with super-exponential growth that ends in collapse. This article is part of the theme issue ‘Evolution and sustainability: gathering the strands for an Anthropocene synthesis’.

Effects of applying a multivariate training program on physical fitness and tactical performance in a team sport taught during physical education classes.

A multivariate training program could be a pedagogical choice to improve physical and tactical performance in a team sport taught during physical education classes at different levels of education. Thus, the aim of this study was to verify the effects of applying a multivariate training program on physical fitness and tactical performance during the teaching of a basketball didactic unit in basic and secondary education. Seventy-five students from a Portuguese school, with an average age of 15.02 ± 1.31 years, included forty-two students from basic school and thirty-three students from secondary school. The FITescola® test battery was used to assess physical fitness (i.e., sit-ups, push-ups, horizontal impulse, shuttle test, 40 m sprint, agility 4 × 10 m). The Game Performance Assessment Instrument (GPAI) was used to assess students' tactical performance for each player's game performance during a 20-minute 3 vs. 3 match. The GPAI variables were decision making index (DMI), skill execution index (SEI), support actions index (SI), and adaptability index (AI). During a basketball didactic unit teaching, the students were randomly divided into two groups, a control group that will not carry out the training program and an experimental group that will carry out a strength training program, high intensity explosive exercises and activities based on small-sided games (SSG) for 6 weeks. The two groups were evaluated in two moments: before the application of the training program and after the application of the training program regarding changes in physical fitness and tactical performance. The independent samples t-test (samples from two groups) and paired sample Test (for the same group) were applied for pre and post-assessment comparisons. All indexes present significant differences between basic and secondary students in the pre- and post-assessment tests with small effects (t = -6.54 to -4.82, Δ = -27.57 to -0.16, p<0.05-p< 0.001, d = 0.78-1.05). The results allow to conclude that in a school environment, a well-structured multivariate training program can effectively improve students' tactical skills, increasing their physical conditioning levels.

Determination of Chemical Explosive Remnants in Soils of Boko Haram’s Affected Areas of Gombe State Nigeria

Aim: This research was conducted to ascertain the level of pollution of our physical environment as a result of years of Boko Haram’s activities in Gombe State, North-Eastern Nigeria.&#x0D; Study Design and Place of Study: Samples for this research were collected from Bajoga, Nafada and Gombe metropolis and environs all in Funakaye, Nafada, and Gombe Local Government Areas respectively. Samples were taken only from places with recorded Boko Haram’s explosion activities. A control sample for each study area was taken from an area that has no record of Boko Haram attacks. Gombe State is located in the North-Eastern part of Nigeria on latitude10015’00’’N and longitude 11010’00’’E bordering Yobe, Borno, Adamawa, Taraba and Bauchi states.&#x0D; Methodology: The concentrations of explosive remnants (4-Nitrotoluene, 4-Propyl Benzaldehyde, 1,3-Dinitrotoluene, 2,4-Dinitrotoluene, 3,5- Dinitrotoluene, Trinitrotoluene, RDX and HMX) in the soil samples of the attacked areas were investigated using Gas Chromatography- Mass Spectrometer, GC-MS.&#x0D; Results: The result indicates 4-Nitrotoluene; 0.05-0.085µg/kg, 4-Propyl Benzaldehyde; 0.07-0.19µg/kg; 1,3-Dinitrotoluene; 0.005-0.060µg/kg, 2,4-DNT; 6.16-6.86µg/kg, 3,5-DNT; 0.40-0.90µg/kg, TNT; 0.29-0.66µg/kg and RDX and HMX were not detected. All the samples in the study area had 4-Nitrotolene and 4-Propyl Benzaldehyde concentrations above those in their respective controls. 1,3-DNT in Bajoga samples, 2,4-DNT in K Police station and K/mata, 3,5-DNT in Gombe metropolis, and TNT in NFD Police station were all found to be below the concentrations in their control&#x0D; Conclusion: There is possible 4-Nitrotolene and 4-Propyl Benzaldehyde contaminations in all the studied sites and absence of pollution by 1,3-DNT in Bajoga, 2,4-DNT in K Police station and K/mata, 3,5-DNT in Gombe metropolis, and TNT in NFD Police station.

Protein production from cellulosic waste using candida utilis

With rapid population growth there is a lot of interest in developing alternative protein sources, like protein yeast cultures. For growth of yeast could be used agricultural and food processing waste, but such source of hydrocarbons need to be pretreated. The purpose of the presented study is to assess the effect of steam explosion treatment on the process of feed protein production, including the influence on the enzymatic hydrolysis, cultivation of yeast and resulting products characteristics. Wheat straw, spelt hull and sunflower husk were subjected to steam explosive activation at 165 °C and 210 °C. The products were subjected to enzymatic hydrolysis at the following conditions: enzyme dose 12 g/kg of raw material and temperature of 45 °C. Total reducing sugars content and component composition were evaluated in the hydrolysates using IR spectrometry and HPLC respectively. A pure yeast culture of Candida utilis, was grown on hydrolysates (2 g/L) in a 10 L bioreactor unit at 35 °C for 24 h. The samples of protein were evaluated for crude protein, true protein, fiber, fat and ash content. Conversion efficiency was calculated. The highest conversion efficiency was observed for spelt husks activated at 165 °C: reducing sugars yield was 56.2 % out of 73.3 % of theoretical yield; biomass concentration reaches 52.9 g/L, with reducing sugar conversion of 80.1 %. The crude protein content of yeast was 53.9 % (42 % according to Barnstein). Hydrolysates from activated materials, give a higher yeast biomass yield of 21–42 % compared to hydrolysates of non-activated raw materials.

Ash Deposition Triggers Phytoplankton Blooms at Nishinoshima Volcano, Japan

AbstractVolcanoes that deposit eruptive products into the ocean can trigger phytoplankton blooms near the deposition area. Phytoplankton blooms impact the global carbon cycle, but the specific conditions and mechanisms that facilitate volcanically triggered blooms are not well understood, especially in low nutrient ocean regions. We use satellite remote sensing to analyze the chlorophyll response to an 8‐month period of explosive and effusive activity from Nishinoshima volcano, Japan. Nishinoshima is an ocean island volcano in a low nutrient low chlorophyll region of the Northern Pacific Ocean. From June to August 2020, during explosive activity, satellite‐derived chlorophyll‐a was detectable with amplitudes significantly above the long‐term climatological value. After the explosive activity ceased in mid‐August 2020, these areas of heightened chlorophyll concentration decreased as well. In addition, we used aerial observations and satellite imagery to demonstrate a spatial correlation between blooms and ash plume direction. Using a sun‐induced chlorophyll‐a fluorescence satellite product, we confirmed that the observed chlorophyll blooms are phytoplankton blooms. Based on an understanding of the nutrients needed to supply blooms, we hypothesize that blooms of nitrogen‐fixing phytoplankton led to a 1010–1012 g drawdown of carbon. Thus, the bloom could have significantly mediated the output of carbon from the explosive phase of the eruption but is a small fraction of anthropogenic CO2 stored in the ocean or the global biological pump. Overall, we provide a case study of fertilization of a nutrient‐poor ocean with volcanic ash and demonstrate a scenario where multi‐month scale deposition triggers continuous phytoplankton blooms across 1,000s of km2.

Central Mediterranean tephrochronology for the time interval 250–315 ka derived from the Fucino sediment succession

In the lacustrine succession F4‐F5 of the Fucino Basin, central Italy, 20 visible tephra layers were identified in the time interval 250–315 ka (Marine Isotope Stages 8–9). Fifteen of them contained suitable material to explore their volcanic sources. Among these tephra some well‐known eruptions and eruptive sequences of the Roman and Roccamonfina volcanoes were identified, such as the Tufo Giallo di Sacrofano and the Lower White Trachytic Tuff, respectively. Furthermore, the sediment succession documents a more complex eruptive history of the Sabatini, Vulsini, Colli Albani and Roccamonfina volcanic complexes during the investigated period, as inferred from previously undescribed tephra deposits. Single‐crystal‐fusion 40Ar/39Ar dating of two of the inspected tephra layers combined with two already published tephra ages provided the basis for a Bayesian age‐depth model. The modelled tephra ages allow chronological constraining of so‐far undefined eruptions of the Sabatini (272.5±4.7, 281.8±4.7, 308.5±2.8, 312.8±2.1 ka), the Vulsini (311.7±2.3, 311.9±2.3 ka) and the Colli Albani (301.0±3.6 ka) volcanic districts. Two tephra layers of an undefined volcanic source from the Roman volcanoes have modelled ages of 309.5±2.7 and 310.5±2.6 ka. The new 40Ar/39Ar and modelled ages were further used for a reassessment of the timing of already known and dated eruptive units, such as the Tufo Giallo di Sacrofano (40Ar/39Ar: 289.3±4.8 ka). Tephra tentatively correlated with the Valle Santa Maria, Case Pisello and the White Trachytic Tuff Unit E3 or Unit F offer modelled ages for these eruptions of 296.6±3.9, 301.8±3.5 and 303.6±3.4 ka, respectively. The results complete the tephrostratigraphical investigations of the c. 425 ka old F4‐F5 record, extend the Mediterranean tephrostratigraphical framework and provide a significant contribution for improving knowledge on Italian volcanic explosive activity.

Fragmentation behavior of young pyroclasts from Mt. Pelée, Martinique

The stratovolcano Mt. Pelée, Martinique, exhibits eruptive styles ranging from dome formation to sustained, highly violent explosive activity. Historical eruptions have produced lava domes and pyroclastic density currents, collectively termed Peléan activity. In pre-colonial times, several Plinian eruptions took place. Here, we explore physical controls on the proportions of fine particles produced—i.e., the fragmentation efficiency—during primary fragmentation. Samples were collected from ignimbrites from the 1929–1932 and 1902–1905 Peléan eruptions and the P1 (1300 CE), P2 (280 CE), and P3 (79 CE) Plinian eruptions. All samples are andesitic in bulk composition and contain a rhyolitic groundmass glass. The Peléan materials are more crystalline and less porous than their Plinian counterparts, a consequence of more extensive outgassing during dome formation. Representative blocks were cored and experimentally fragmented following rapid decompression (> 1 GPa·s−1 from initial pressure between 5 and 20 MPa). Dry sieving allowed for determining grain size distributions, from which the fractal dimensions, Df, were calculated as a quantification of fragmentation efficiency. Our results indicate different behaviors for Peléan and Plinian samples. While fragmentation efficiency is positively correlated with applied potential energy for Peléan samples, this relationship is not observed for the Plinian samples, possibly due to syn-fragmentation gas escape above a certain porosity. The rapid decompression experiments were designed to minimize secondary fragmentation by shear along the walls or impact while preserving the entirety of produced materials. Thus, our experimental grainsize data are physically linked to sample textures and overpressure. By comparison with natural pyroclastic products—commonly incompletely preserved—we can approach quantitatively constraining the energetic conditions underlying individual eruptions.

A review of ergogenic nutritional supplements for athletes

Ergogenic supplements are defined as substances that contribute to or support the doing or production of a job. These supplements are used for many purposes such as increasing the performance of athletes, accelerating recovery in athletes, improving capacity, and reducing and preventing muscle injuries and muscle fatigue. Ergogenic supplements, which are of great interest to athletes and trainers, are classified as nutritional aids, pharmacological aids, psychological aids, mechanical and biomechanical aids, and physiological aids. Among these supplements, they are the most actively used nutritional aids and attract attention in the market as muscle-building nutritional supplements, weight-reducing nutritional supplements, performance-enhancing nutritional supplements, and general health-promoting nutritional supplements. Protein and amino acids provide benefits in long-term or short-term explosive power activities. Fats are used as the main fuel in long-term aerobic exercises. In addition, caffeine, ginseng, antioxidants, and coenzyme Q10 also serve as ergogenic nutritional supplements. It has been reported in studies that minerals such as B, C and E vitamins, chromium, magnesium, iron, and zinc affect sports performance in a good way. In case of deficiency of the aforementioned vitamins and minerals in athletes, many negativities occur. In this study, the use of ergogenic nutritional supplements by athletes before, during, and after training was compiled using the current literature on the types of these supplements.

Statistical Insights on the Eruptive Activity at Stromboli Volcano (Italy) Recorded from 1879 to 2023

Stromboli is an open-conduit active volcano located in the southern Tyrrhenian Sea and is the easternmost island of the Aeolian Archipelago. It is known as “the lighthouse of the Mediterranean” for its continuous and mild Strombolian-type explosive activity, occurring at the summit craters. Sometimes the volcano undergoes more intense explosions, called “major explosions” if they affect just the summit above 500 m a.s.l. or “paroxysms” if the whole island is threatened. Effusive eruptions are less frequent, normally occurring every 3–5 years, and may be accompanied or preceded by landslides, crater collapses and tsunamis. Given the small size of the island (maximum diameter of 5 km, NE–SW) and the consequent proximity of the inhabited areas to the active craters (maximum distance 2.5 km), it is of paramount importance to use all available information to forecast the volcano’s eruptive activity. The availability of a detailed record of the volcano’s eruptive activity spanning some centuries has prompted evaluations on its possible short-term evolution. The aim of this paper is to present some statistical insights on the eruptive activity at Stromboli using a catalogue dating back to 1879 and reviewed for the events during the last two decades. Our results confirm the recent trend of a significant increase in major explosions, small lava flows and summit crater collapses at the volcano, and might help monitoring research institutions and stakeholders to evaluate volcanic hazards from eruptive activity at this and possibly other open-vent active basaltic volcanoes.

The Effects of Massage Guns on Performance and Recovery: A Systematic Review.

The use of massage guns has become increasingly popular in recent years. Although their use is more and more common, both in a clinical and sports context, there is still little information to guide the practitioners. This systematic review aimed to determine the effects of massage guns in healthy and unhealthy populations as pre- and post-activity or part of a treatment. Data sources used were PubMed, PEDro, Scopus, SPORTDiscus, Web of Science and Google Scholar, and the study eligibility criteria were based on "healthy and unhealthy individuals", "massage guns", "pre-activity, post-activity or part of a treatment" and "randomized and non-randomized studies" (P.I.C.O.S.). Initially, 281 records were screened, but only 11 could be included. Ten had a moderate risk of bias and one a high risk of bias. Massage guns could be effective in improving iliopsoas, hamstrings, triceps suralis and the posterior chain muscles' flexibility. In strength, balance, acceleration, agility and explosive activities, it either did not have improvements or it even showed a decrease in performance. In the recovery-related outcomes, massage guns were shown to be cost-effective instruments for stiffness reduction, range of motion and strength improvements after a fatigue protocol. No differences were found in contraction time, rating of perceived exertion or lactate concentration. Massage guns can help to improve short-term range of motion, flexibility and recovery-related outcomes, but their use in strength, balance, acceleration, agility and explosive activities is not recommended.

Temporal change in eruption style during the basaltic explosive An’ei eruption of the Izu-Oshima volcano, Japan: insights from stratigraphy and chemical composition analyses

Basaltic eruptions sometimes show an explosive and complex nature; thus, clarifying the sequence and controlling parameters is essential for understanding their causes. The An’ei eruption of the Izu-Oshima volcano during 1777–1792 was a complex basaltic eruption producing lava flows, pyroclastic falls, and ash plumes. We reconstructed the transition of the eruption style based on geological data combined with comparisons with data from historical documents and used chemical analyses to develop a magma plumbing model. The An’ei eruption started in August 1777 with scoria ejection. The scoria deposit was classified into Units A–C. Unit A scoria was produced by early weak explosions and more intense subsequent explosions. Unit B scoria marked a return to weak plumes before the summit eruption reached its climactic phase in November 1778 and explosively ejected Unit C scoria. Several lava flows were also effused from the foot of the scoria cone during these periods of scoria ejection. After a 5-year hiatus, the eruption ultimately shifted to persistent, weak ash ejection and pyroclastic surges. The tephra volumes of Units A, B, and C were estimated at 1.9–4.3 × 107, 0.6–4.5 × 106, and 1.3–3.2 × 107 m3, respectively. Associated column heights of 8–11, 3–10, and 9–12 km were obtained for Units A, B, and C, respectively, resulting in sub-Plinian classification. Chemical analyses have shown that the plagioclase phenocryst content increased as the eruption progressed. The transition from relatively weak activity with Strombolian and sub-Plinian explosions, caused by aphyric magma, to short-period activity with more intense sub-Plinian explosions, caused by porphyritic magma, can be explained by evacuation of magma from multiple reservoirs with different contents of plagioclase phenocrysts. Simultaneous lava flows that have different petrological features from those of the scoria eruptions also suggest multiple magma reservoirs and pathways. This view of the temporal change in eruptive style, corresponding to change in magma type, is essential for understanding the eruptive processes of large-scale basaltic eruptions of the Izu-Oshima volcano and contributes to clarifying the nature and hazards of basaltic eruptions which turn into explosive activities in general.

Temporal variability of explosive activity at Tajogaite volcano, Cumbre Vieja (Canary Islands), 2021 eruption from ground-based infrared photography and videography

The 2021 eruption at Tajogaite (Cumbre Vieja) volcano (La Palma, Spain) was characterized by Strombolian eruptions, Hawaiian fountaining, white gas-dominated and grey ash-rich plumes, and lava effusion from multiple vents. The variety of eruptive styles displayed simultaneously and throughout the eruption presents an opportunity to explore controls on explosivity and the relationship between explosive and effusive activity. Explosive eruption dynamics were recorded using ground-based thermal photography and videography. We show results from the analysis of short (&lt;5 min) near-daily thermal videos taken throughout the eruption from multiple ground-based locations and continuous time-lapse thermal photos over the period November 16 to November 26. We measure the apparent radius, velocity, and volume flux of the high-temperature gas-and-ash jet and lava fountaining behaviors to investigate the evolution of the explosive activity over multiple time scales (seconds-minutes, hours, and days-weeks). We find fluctuations in volume flux of explosive material that correlate with changes in volcanic tremor and hours-long increases in explosive flux that are immediately preceded by increases in lava effusion rate. Correlated behavior at multiple vents suggests dynamic magma ascent pathways connected in the shallow (tens to hundreds of meters) sub-surface. We interpret the changes in explosivity and the relative amounts of effusive and explosivity to be the result of changes in gas flux and the degree of gas coupling.

Turonian highly differentiated pyroclastic xenoliths and Cretaceous sedimentary record challenge mantle-plume view of Costa Rican forearc basement successions

The Mesozoic basaltic basement of southern Central America is believed to consist of proxy sections of mantle-plume events leading to the Caribbean igneous province. A significant xenolith assemblage of radiolarite, tuffite, and Turonian (∼93 Ma) highly differentiated pyroclastic rock discovered in basalt of the Costa Rican forearc basement fundamentally challenge this long-held view, revealing bimodal Cretaceous island-arc activity and forearc basin development instead. The pyroclastic materials originally accumulated with monotonous radiolarite deposits in a deep-marine forearc basin slope environment to build part of the Mesozoic sedimentary cover of the evolving arc. Xenolith formation was related to widespread Turonian to Campanian intrusive basaltic activity on the Nicoya Peninsula that affected Albian-Turonian and Berriasian-Barremian radiolarite and pyroclastic deposits as well as Jurassic siliceous strata. Strong correlation with Cretaceous biotite- and hornblende-bearing pyroclastic beds reveals explosive calc-alkaline volcanic arc episodes alongside basaltic activity linked to marine forearc basin development. These materials provide decisive evidence of explosive calc-alkaline volcanic activity of the Cretaceous Costa Rican arc as well as the probable intraoceanic-arc nature of its basaltic forearc basement and a ∼90 Ma aged komatiite suite found at Tortugal. The resulting tectonic scenario shows the Caribbean Plate was separated in southern Central America from any potential Pacific or Galápagos hotspot sources by a subduction zone. This favours in-place origin of the Caribbean Plate and its igneous province between the Americas. The findings also reveal the unsuitability of basaltic forearc basement successions to deduce with certainty mantle-plume events and hotspot evolutions in adjoining oceanic domains.

Volcanology and facies analysis of the youngest phreatomagmatic deposits on O'ahu, Hawai'i

The area known as the Lānaʻi Lookout has Oʻahu's youngest and best exposures of deposits from pyroclastic density currents (PDCs), generated by explosions involving magma-water interaction. This work presents the first detailed facies analysis of the deposits at the Lānaʻi Lookout, fundamental to understanding the explosion dynamics, post-fragmentation transport and depositional processes, and to unravel the eruptive history. The lithofacies identified include planar-bedded, low-angle, and megaripple, cross-bedded ash to lapilli, accretionary lapilli-rich falls and isolated ballistic blocks and bombs. These features are interpreted as generated by mostly dilute PDCs, co-PDC fall and sedimentation from eruptive clouds and ballistic-charged jets. Overall, at least four eruptive stages formed the pyroclastic succession: (i) frequent, brief explosions from Kahauloa and Koko craters, producing fallout deposits and ballistics; (ii) a dominant stage of sustained passing to short-lived production of PDCs from Kahauloa crater, followed by a short break in volcanic activity; (iii) return of explosive activity dominated by fallout deposits likely sourced at Kahauloa; (iv) intermittent PDCs from Kahauloa alternating with debris flows coming down Koko Crater flanks. This stage is followed by lava flow emplacement that marked the end of the explosive eruptions at the Koko Rift system. In summary, the lithofacies analysis and stratigraphic relations of this complex multi-vent system informs on the dynamics, eruptive style, and frequency of eruptions of the late-stage volcanism on Oʻahu.

BOOM! Tephrochronological dataset and exploration tool of the Southern (33–46° S) and Austral (49–55° S) volcanic zones of the Andes

Tephrochronology studies the deposits of explosive volcanic eruptions in the stratigraphic record. The Southern (SVZ, 33–46° S) and Austral (AVZ, 49–55° S) Volcanic Zones of the Andes are two very active volcanic zones where tephrochronology is of great use. There, it can be used to improve chronologies of paleoenvironmental records in Patagonia, an area providing valuable records at global scale; as well as to identify areas likely to be affected by volcanic eruptions in the future, essential for producing volcanic hazard maps. The close proximity of many volcanic centers with recurrent explosive activity, which have very similar geochemical compositions, and very often poor age constraints, represent a challenge for the study of tephrochronology in the region. In addition to this, the ever-growing amount of tephrochronological information in the area, dispersed in different types of publications which vary greatly in format, makes the integration of the data produced by different actors, and consecutively its interpretation, increasingly difficult. Here we address this issue by compiling the BOOM! dataset, which integrates ∼30 years of research on 32 active volcanic centers and 132 different eruptions, which took place during the last 20,000 years. To help users find and reuse data in the large dataset, we developed an online platform which provides user-friendly tools for exploring it, and helps users download subsets of it. To integrate this very heterogeneous information, special attention was given to include information which allows users to evaluate data quality and comparability, as well as to provide tools in the explorer for users to filter data by different criteria. The integration of this dataset opens new perspectives for the development of novel visualizations of tephrochronological data, for example, to better understand the multidimensional uncertainties associated with it. For example, uncertainties associated with analytical precision, with age estimates of both tephra deposits and volcanic eruptions, and of tephra classification. Additionally, it allows for the use of robust statistical tools to correlate tephra deposits, including those based on machine learning algorithms, which are here explored.