The eruptions of Eyjafjallajökull volcano in 2010 (including its initial effusive phase at Fimmvörðuháls and its later explosive phase from the central volcano) and Bárðarbunga volcano in 2014–2015 ...(at Holuhraun) were widely reported. Here, we report on complementary, interdisciplinary observations made of the eruptive gases and lavas that shed light on the processes and atmospheric impacts of the eruptions, and afford an intercomparison of contrasting eruptive styles and hazards. We find that (i) consistent with other authors, there are substantial differences in the gas composition between the eruptions; namely that the deeper stored Eyjafjallajökull magmas led to greater enrichment in Cl relative to S; (ii) lava field SO
2
degassing was measured to be 5–20% of the total emissions during Holuhraun, and the lava emissions were enriched in Cl at both fissure eruptions—particularly Fimmvörðuháls; and (iii) BrO is produced in Icelandic plumes in spite of the low UV levels.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Recent Icelandic rifting events have illuminated the roles of centralized crustal magma reservoirs and lateral magma transport
, important characteristics of mid-ocean ridge magmatism
. A consequence ...of such shallow crustal processing of magmas
is the overprinting of signatures that trace the origin, evolution and transport of melts in the uppermost mantle and lowermost crust
. Here we present unique insights into processes occurring in this zone from integrated petrologic and geochemical studies of the 2021 Fagradalsfjall eruption on the Reykjanes Peninsula in Iceland. Geochemical analyses of basalts erupted during the first 50 days of the eruption, combined with associated gas emissions, reveal direct sourcing from a near-Moho magma storage zone. Geochemical proxies, which signify different mantle compositions and melting conditions, changed at a rate unparalleled for individual basaltic eruptions globally. Initially, the erupted lava was dominated by melts sourced from the shallowest mantle but over the following three weeks became increasingly dominated by magmas generated at a greater depth. This exceptionally rapid trend in erupted compositions provides an unprecedented temporal record of magma mixing that filters the mantle signal, consistent with processing in near-Moho melt lenses containing 10
-10
m
of basaltic magma. Exposing previously inaccessible parts of this key magma processing zone to near-real-time investigations provides new insights into the timescales and operational mode of basaltic magma systems.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The Icelandic Meteorological Office maintains a national network of webcams designed and built in house for environmental monitoring. During the 2021 Fagradalsfjall eruption these cameras, along with ...a temporary near-field network of commercial cameras installed by the Department of Civil Protection and Emergency Management, were used to estimate the height of the
S
O
2
plume and lava fountain. Here we present the webcam designs, the techniques used to calibrate them, and the messaging system and web interface that allow near real time measurements to be made from the images. With this system we were able to make estimates of heights with an accuracy on the order of tens to a few hundreds of meters with a lag typically of five to ten minutes at up to ten minute intervals when weather conditions were favorable. The plume heights were then used to constrain the performance of the
S
O
2
dispersion model used for air quality forecasts while fountain heights were used to delineate danger zones where visitors at the eruption site were in danger of being hit by ballistic clasts.
Volcanoes are a key natural source of CO2, but global estimates of volcanic CO2 flux are predominantly based on measurements from a fraction of world's actively degassing volcanoes. We combine ...high‐precision airborne measurements from 2016 and 2017 with atmospheric dispersion modeling to quantify CO2 emissions from Katla, a major subglacial volcanic caldera in Iceland that last erupted 100 years ago but has been undergoing significant unrest in recent decades. Katla's sustained CO2 flux, 12–24 kt/d, is up to an order of magnitude greater than previous estimates of total CO2 release from Iceland's natural sources. Katla is one of the largest volcanic sources of CO2 on the planet, contributing up to 4% of global emissions from nonerupting volcanoes. Further measurements on subglacial volcanoes worldwide are urgently required to establish if Katla is exceptional, or if there is a significant previously unrecognized contribution to global CO2 emissions from natural sources.
Plain Language Summary
We discovered that Katla volcano in Iceland is a globally important source of atmospheric carbon dioxide (CO2) in spite of being previously assumed to be a minor gas emitter. Volcanoes are a key natural source of atmospheric CO2, but estimates of the total global amount of CO2 that volcanoes emit are based on only a small number of active volcanoes. Very few volcanoes that are covered by glacial ice have been measured for gas emissions, probably because they tend to be difficult to access and often do not have obvious degassing vents. Through high‐precision airborne measurements and atmospheric dispersion modeling, we show that Katla, a highly hazardous subglacial volcano that last erupted 100 years ago, is one of the largest volcanic sources of CO2 on Earth, releasing up to 4% of total global volcanic emissions. This is significant in a context of a growing awareness that natural CO2 sources have to be more accurately quantified in climate assessments, and we recommend urgent investigations of other subglacial volcanoes worldwide.
Key Points
Subglacial volcanoes are underrepresented in terms of gas monitoring, but we show that they can be major emitters of CO2
Katla volcano is found to be one of largest volcanic sources of CO2 on the planet, contributing up to 4% of all nonerupting volcanoes
High‐precision airborne measurements combined with atmospheric modeling are a powerful method to monitor poorly accessible volcanoes
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The Krýsuvík volcanic system is located on the oblique spreading Reykjanes Peninsula, SW Iceland. Since early 2009 the region has been undergoing episodes of localized ground uplift and subsidence. ...From April–November 2013, we operated near-real time monitoring of gas emissions in Krýsuvík, using a Multi-component Gas Analyzer System (Multi-GAS), collecting data on gas composition from a fumarole (H2O, CO2, SO2, H2S). The dataset in this study, comprises a near-continuous gas composition time series, the quantification of diffuse CO2 gas flux, analytical results for direct samples of dry gas, seismic records, and GPS data. Gas emissions from the Krýsuvík geothermal system were examined and compared with crustal deformation and seismicity.
The gas emissions from the Krýsuvík system are H2O-dominated, with CO2 as the most abundant dry gas species, followed by smaller concentrations of H2S. The average subsurface equilibrium temperature was calculated as 278 °C. This is consistent with previous observations made through sporadic spot sampling campaigns. In addition, the semi-continuous Multi-GAS dataset reveals higher variations in gas composition than previously reported by spot sampling.
The diffuse soil CO2 flux is found to be variable between the three studied degassing areas in Krýsuvík, ranging from 10.9–70.9 T/day, with the highest flux in Hveradalir where the Multi-GAS station is located. The total flux is estimated as 101 T/day.
Comparison between Multi-GAS and geophysical data shows that peaks of H2O-rich emissions appears to follow crustal movements. Coinciding with the H2O-rich peaks, SO2 is detected in minor amounts (~0.6 ppmv), allowing for calculations of H2O/SO2, CO2/SO2 and H2S/SO2 ratios. This is the first time SO2 has been detected in the Krýsuvík area.
The large variations in H2O/CO2 and H2O/H2S ratios are considered to reflect variable degassing activity in the fumarole. The activity of the fumarole appears less intense during intervals of low or no recorded seismic events. The H2O/CO2 and H2O/H2S ratios are lower, presumably due to H2O condensation affecting the steam jet before reaching the Multi-GAS inlet tube.
•Gas emissions from Krýsuvík are H2O-dominated, with CO2 as the most abundant dry gas species, followed by smaller concentrations of H2S. Gas geothermometers indicate subsurface temperature of 278 °C.•The degassing regime in Krýsuvík is highly variable over short timescales, with changes in fumarole activity and fluctuations in gas composition which is linked to variations in seismicity and ground deformation.•The diffuse soil CO2 flux from the three studied degassing areas in Krýsuvík, is ranging from 10.9–70.9 T/day.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Civilian public mass shootings (CPMSs) in the US result in substantial injuries. However, the types and consequences of these injuries have not been systematically described.
To describe the injury ...characteristics, outcomes, and health care burden associated with nonfatal injuries sustained during CPMSs and to better understand the consequences to patients, hospitals, and society at large.
This retrospective case series of nonfatal injuries from 13 consecutive CPMSs (defined as ≥10 injured individuals) from 31 hospitals in the US from July 20, 2012, to August 31, 2019, used data from trauma logs and medical records to capture injuries, procedures, lengths of stay, functional impairment, disposition, and charges. A total of 403 individuals treated in hospitals within 24 hours of the CPMSs were included in the analysis. Data were analyzed from October 27 to December 5, 2021.
Nonfatal injuries sustained during CPMSs.
Injuries and diagnoses, treating services, procedures, hospital care, and monetary charges.
Among the 403 individuals included in the study, the median age was 33.0 (IQR, 24.5-48.0 range, 1 to >89) years, and 209 (51.9%) were women. Among the 386 patients with race and ethnicity data available, 13 (3.4%) were Asian; 44 (11.4%), Black or African American; 59 (15.3), Hispanic/Latinx; and 270 (69.9%), White. Injuries included 252 gunshot wounds (62.5%) and 112 other injuries (27.8%), and 39 patients (9.7%) had no physical injuries. One hundred seventy-eight individuals (53.1%) arrived by ambulance. Of 494 body regions injured (mean SD, 1.35 0.68 per patient), most common included an extremity (282 57.1%), abdomen and/or pelvis (66 13.4%), head and/or neck (65 13.2%), and chest (50 10.1%). Overall, 147 individuals (36.5%) were admitted to a hospital, 95 (23.6%) underwent 1 surgical procedure, and 42 (10.4%) underwent multiple procedures (1.82 per patient). Among the 252 patients with gunshot wounds, the most common initial procedures were general and trauma surgery (41 16.3%) and orthopedic surgery (36 14.3%). In the emergency department, 148 of 364 injured individuals (40.7%) had 199 procedures (1.34 per patient). Median hospital length of stay was 4.0 (IQR, 2.0-7.5) days; for 50 patients in the intensive care unit, 3.0 (IQR, 2.0-8.0) days (13.7% of injuries and 34.0% of admissions). Among 364 injured patients, 160 (44.0%) had functional disability at discharge, with 19 (13.3%) sent to long-term care. The mean (SD) charges per patient were $64 976 ($160 083).
Civilian public mass shootings cause substantial morbidity. For every death, 5.8 individuals are injured. These results suggest that including nonfatal injuries in the overall burden of CPMSs may help inform public policy to prevent and mitigate the harm caused by such events.
Gas and particulate matter (PM) emissions from Masaya volcano, Nicaragua, cause substantial regional volcanic air pollution (VAP). We evaluate the suitability of low-cost SO2 and PM sensors for a ...continuous air-quality network. The network was deployed for six months in five populated areas (4-16 km from crater). The SO2 sensors failed and recorded erroneous values on multiple occasions, likely due to corrosion, requiring significant maintenance commitment. The PM sensors were found to be robust but data required correction for humidity. SO2 measurements could not be used as stand-alone tools to detect occurrence of VAP episodes (VAPE), but SO2/PM correlation reliably achieved this at near-field stations, as confirmed by meteorological forecasts and satellite imagery. Above-background PM concentrations reliably identified VAPE at both near-field and far-field stations. We suggest that a continuous network can be built from a combination of low-cost PM and SO2 sensors with a greater number of PM-only sensors.
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