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Observations of the loss of stratospheric NO2 following volcanic eruptions

Observations of stratospheric column amounts of nitrogen dioxide (NO2), nitric oxide (NO) and nitric acid (HNO3) have been made following major eruptions of the El Chichon and Mt. Pintatubo volcanoes. Midlatitude abundances of NO2 and NO were reduced by as much as 70% in the months following the appearance of the volcanic aerosols as compared to volcanically quite periods. There are heterogeneous reactions which could occur on the volcanic aerosols to convert NO2 into HNO3 but no commensurate increase in HNO3 column amounts was observed at the times of NO2 decrease.

Coffey, M. T.↗

A Recent Volcanic Eruption, Holuhraun, in the Central Highlands of Iceland as a Mars analog: The 2018 Field Campaign of FELDSPAR

In summer 2018, FELDSPAR conducted an analog sampling expedition to the Holuhraun volcanoin the central highlands of Iceland that erupted from August 2014 to February 2015. Holuhraun hassteep gradients within an otherwise relatively controlled region, and thus served as the primaryMars analog site for the 2018 FELDSPAR field campaign. Samples along gradients of mineralogyas measured via near-IR and visible reflectance spectroscopy, temperature as measured by an IRprobe, and physical location about the fissure (slope incline, directionality, height up the slope,etc.) were analyzed in-field with reflectance spectroscopy and X-ray fluorescence, in the field labfor adenosine trisphosphate (ATP) as an indicator of metabolic activity, and after return to thehome lab for both geochemical and geophysical parameters (moisture content, grain size, X-raydiffraction) and biochemical parameters (DNA content and speciation). This abstract representsthe first report on the 2018 field campaign with initial results and interpretation. This work is part ofField Exploration and Life Detection Sampling for Planetary Analogue Research (FELDSPAR), onFacebook @FELDSPAResearch.

Volcanic↗

IMS observations of infrasound and acoustic-gravity waves produced by the January 2022 volcanic eruption of Hunga, Tonga: A global analysis

The 15 January 2022 Hunga, Tonga, volcano's explosive eruption produced the most powerful blast recorded in the last century, with an estimated equivalent TNT yield of 100–200 megatons. The blast energy was propagated through the atmosphere as various wave types. The most prominent wave was a long-period (>2000 s) surface-guided Lamb wave with energy comparable to that of the 1883 Krakatoa Lamb wave; both were clearly observed by pressure sensors (barometers) worldwide. Internal gravity, acoustic-gravity, and infrasound waves were captured in great detail by the entire infrasound component of the International Monitoring System (IMS). For instance, infrasound waves (<300 s period) were seen to circumnavigate Earth up to eight times. Atmospheric waves captured by the IMS infrasound network and selected barometers near the source provide insight on Earth's impulse response at planetary scales.

58 GEOSCIENCES↗

Multi-Event Explosive Seismic Source for the 2022 M w 6.3 Hunga Tonga Submarine Volcanic Eruption

The eruption of the Hunga Tonga–Hunga Ha’apai submarine volcano on 15 January 2022 produced a variety of geophysical responses, including a significant seismic signal. We study the seismic source process of this event by inverting for moment tensors (MTs) using regional surface waves (Rayleigh, Love). By comparing inversion results for the eruption with eight nearby earthquakes, we show that it is possible to discriminate MT source types. Our inversion yields a shallow explosive source for the eruption and reveals the importance of trade-offs among depth, magnitude, and source type. We illustrate these trade-offs by representing the misfit variations over the eigenvalue lune. Finally, we invert for the source-time function of the sequence of explosions that occurred in the first minutes of the eruption. The multi-event source-time function comprises four subevents spanning ~270 s, with a total magnitude estimate of M w 6.34 ± 0.10.

58 GEOSCIENCES↗

An investigation of thermal anomalies in the Central American volcanic chain and evaluation of the utility of thermal anomaly monitoring in the prediction of volcanic eruptions

The author has identified the following significant results. Ground truth data collection proves that significant anomalies exist at 13 volcanoes within the test site of Central America. The dimensions and temperature contrast of these ten anomalies are large enough to be detected by the Skylab 192 instrument. The dimensions and intensity of thermal anomalies have changed at most of these volcanoes during the Skylab mission.

Stoiber, R. E.↗

Modeling lunar volcanic eruptions

Simple physical arguments are used to show that basaltic volcanos on different planetary bodies would fountain to the same height if the mole fraction of gas in the magma scaled with the acceleration of gravity. It is suggested that the actual eruption velocities and fountain heights are controlled by the velocities of sound in the two phase gas/liquid flows. These velocities are in turn determined by the gas contents in the magma. Predicted characteristics of Hawaiian volcanos are in excellent accord with observations. Assuming that the only gas in lunar volcano is the CO which would be produced if the observed Fe metal in lunar basalts resulted from graphite reduction, lunar volcanos would fountain vigorously, but not as spectacularly as their terrestrial counterparts. The volatile trace metals, halogens, and sulfur released would be transported over the entire moon by the transient atmosphere. Orange and black glass type pyroclastic materials would be transported in sufficient amounts to produce the observed dark mantle deposits.

Housley, R. M.↗

A two-dimensional model simulation of the EL Chichon volcanic eruption cloud

Using a two-dimensional model of sulfate photochemistry, transport, and aerosol microphysics, a 2-year period following the eruptions of El Chichon have been simulated. Present calculations suggest that the residence time of the cloud in the stratosphere exceeds 2 years. The model reproduces the observed optical depth, lidar backscatter, and infrared extinction coefficients, if about 10 megatonnes of SO2 are injected. The major deficiency of the model is a somewhat too rapid transport.

Capone, L. A.↗

Detection of volcanic eruptions from space by their sulfur dioxide clouds

The capabilities of the total ozone mapping spectrometer (TOMS) on the Nimbus 7 satellite for tracking volcano plumes are assessed. TOMS was installed on the sun-synchronous polar orbiting satellite to measure spatial variations in the global total ozone field. Radiance absorption coefficients of the atmosphere for four near-UV wavelengths from 312.5-380.0 are measured. Data from the El Chichon eruption in March-April 1982 revealed that SO2 was an absorbing species at 312.5 and 317.5 nm. The near-UV absorption level differences between SO2 and O3 permit discriminating the atmospheric densities of each species. An examination of the data base generated by TOMS since 1978 showed the perceptible tracks of all known major eruptions in the 1978-1982 time period. A constellation of three of the polar orbiting TOMS would be sufficient to provide near-real time alerts of plumes to warn aircraft of the hazards.

Krueger, A. J.↗

Comparison of the impact of volcanic eruptions and aircraft emissions on the aerosol mass loading and sulfur budget in the stratosphere

Data obtained by the Stratospheric Aerosol and Gas Experiment (SAGE) 1 and 2 were used to study the temporal variation of aerosol optical properties and to assess the mass loading of stratospheric aerosols from the eruption of volcanos Ruiz and Kelut. It was found that the yearly global average of optical depth at 1.0 micron for stratospheric background aerosols in 1979 was 1.16 x 10(exp -3) and in 1989 was 1.66 x 10(exp -3). The eruptions of volcanos Ruiz and Kelut ejected at least 5.6 x 10(exp 5) and 1.8 x 10(exp 5) tons of materials into the stratosphere, respectively. The amount of sulfur emitted per year from the projected subsonic and supersonic fleet is comparable to that contained in the background aerosol particles in midlatitudes from 35 deg N to 55 deg N.

Yue, Glenn K.↗

Mars: Review and analysis of volcanic eruption theory and relationships to observed landforms

We present a theoretical treatment of the ascent, emplacement, and eruption of magma on Mars. Because of the lower gravity, fluid convective motions and crystal settling processes driven by positive and negative buoyancy forces, as well as overall diapiric ascent rates, will be slower on Mars than on Earth, permitting larger diapirs to ascend to shallower depths. Martian environmental conditions operate to modulate the various eruption styles and the morphology and morphometry of resulting landforms, providing new insight into several volcanological problems.

Wilson, Lionel↗

Implication of the January 1990 Volcanic Eruption on Io for Resurfacing Rates and Energetics

The high temperature event observed by ground based infrared radiometry of Io in January of 1990 can be modeled as an extremely active silicate lava flow which increased its area and cooled over a period of three hours. The best model at the start of the observations is a thermal source at 1200 K with an area equal to that of a circle of 5.6 km radius, while at the end of the observation sequence a source with a temperature of 700 K and a 13 km radium provides the best match. Given a flow thickness of 10 m, this implies an eruption rate of 300,000 cubic meters per second. This is large by terrestrial standards but consistent with estimates of lunar eruption rates (Head and Wilson 1981) and some terrestrial eruptions such as the 1800-1801 Hualalai flow in Hawaii (Baloga and Spudis 1992)...

Johnson, T. V.↗