Geology of Ascutney Mountain

Guidebook, forty-sixth annual conference, October 9-10, 1954: Trip

The 1966 eruption of Izalco Volcano, El Salvador

During October–November 1966 900,000 m3 of olivine basalt flowed from the flank of Izalco volcano, El Salvador. The total heat energy was approximately 1015 calories. No measurable changes in gravity occurred at stations on the active cone between August 1964 and August 1967. In the summit crater fumaroles have surface temperatures as high as 540°C. The cooling rate of these fumaroles was 18°C/yr before the eruption and 45°C/yr after. Yearly temperature cycles due to wet and dry seasons are superimposed on the general cooling trend. The rate of gas emission at four fumaroles in November 1967 was 86 g/sec. The data from fumaroles and the volume of the flank eruption indicate that the volume of the high-level magma storage beneath the crater was 3.8×106 metric tons before the eruption and 1.4×106 metric tons after. Four of the larger hot fumaroles contribute at least 10% of the heat loss from the high-level magma storage, whereas heat conduction accounts for more than half the total loss

Atmospheric implications of studies of Central American volcanic eruption clouds

During February 1978 a group of scientists from the National Center for Atmospheric Research, several colleges and universities, the U.S. Geological Survey, and NASA used a specially equipped Beech Queen Air aircraft to make 11 sampling flights in Guatemala through the eruption clouds from the volcanoes Pacaya, Fuego, and Santiguito. Measurements were made of SO42−, SO2, HCl, HF, and 11 cations that were in water-soluble form, on samples collected by a specially designed filter pack. Particle size distributions were obtained with a piezoelectric cascade impactor, and the particles were identified by energy dispersive X ray analysis. Evacuated canisters were flown to obtain samples for gas Chromatographic analysis. Some of the conclusions reached are that since most of the sulfur was found to be in the form of SO2, the H2SO4 droplets resulting from major explosive eruptions must largely result from the reaction of SO2 with OH, at the same time depleting the atmosphere of OH; the volume concentration ratio [SO2]/[HCl] always somewhat exceeded unity; and the amount of fine ash remaining in the stratosphere for long periods of time may depend on the crystallinity of the magma. Correlation spectrometry showed that each volcano was emitting 300–1500 metric tons of SO2 per day

Research on atmospheric volcanic emissions: An overview

The project Research on Atmospheric Volcanic Emissions is a unique effort by NASA and university scientists to investigate the detailed chemical nature of plumes from volcanic eruptions. The major goals of the project are to: 1) understand the impact major eruptions will have on atmospheric chemistry processes, 2) understand the importance of volcanic emissions in the atmospheric geochemical cycles of selected species, 3) use knowledge of the plume chemical composition to diagnose and predict magmatic processes. Project RAVE\u27S first mission used the NASA Lockheed Orion P-3 outfitted with equipment to measure concentrations of the gases SO2, OCS, H2S, CS2, NO, O3and trace elements in particles in Mt. St. Helens\u27 plume on September 22, 1980. Measurements of SO2 column densities in the plume permitted calculations of SO2 fluxes. This article is an overview of the first experimental design factors and performance of the initial RAVE experiment

STAT3/LKB1 controls metastatic prostate cancer by regulating mTORC1/CREB pathway

Prostate cancer (PCa) is a common and fatal type of cancer in men. Metastatic PCa (mPCa) is a major factor contributing to its lethality, although the mechanisms remain poorly understood. PTEN is one of the most frequently deleted genes in mPCa. Here we show a frequent genomic co-deletion of PTEN and STAT3 in liquid biopsies of patients with mPCa. Loss of Stat3 in a Pten-null mouse prostate model leads to a reduction of LKB1/pAMPK with simultaneous activation of mTOR/CREB, resulting in metastatic disease. However, constitutive activation of Stat3 led to high LKB1/pAMPK levels and suppressed mTORC1/CREB pathway, preventing mPCa development. Metformin, one of the most widely prescribed therapeutics against type 2 diabetes, inhibits mTORC1 in liver and requires LKB1 to mediate glucose homeostasis. We find that metformin treatment of STAT3/AR-expressing PCa xenografts resulted in significantly reduced tumor growth accompanied by diminished mTORC1/CREB, AR and PSA levels. PCa xenografts with deletion of STAT3/AR nearly completely abrogated mTORC1/CREB inhibition mediated by metformin. Moreover, metformin treatment of PCa patients with high Gleason grade and type 2 diabetes resulted in undetectable mTORC1 levels and upregulated STAT3 expression. Furthermore, PCa patients with high CREB expression have worse clinical outcomes and a significantly increased risk of PCa relapse and metastatic recurrence. In summary, we have shown that STAT3 controls mPCa via LKB1/pAMPK/mTORC1/CREB signaling, which we have identified as a promising novel downstream target for the treatment of lethal mPCa

Fumarole incrustations at active central american volcanoes

In 11 yr of sampling at 14 volcanoes in Guatemala, El Salvador, Nicaragua and Costa Rica, we have identified 47 minerals in incrustations depositing at approximately 100 different high temperature fumaroles. Most of these minerals are sulfates. The most abundant and most frequently found minerals are: sulfur, hematite, halite, sylvite, gypsum, ralstonite, anhydrite, thenardite and langbeinite. Incrustation suites deposit around fumaroles to produce a zonal pattern which is a response to the rapidly changing temperature and oxygen pressure at the mouth of the vent. The observed zoning pattern can be explained by the reaction of a volcanic gas composed of H2O, SO2, CO2, HC1 and HF, along with trace amounts of volatile cations, which interacts with the atmosphere and the fumarole wallrock. This interaction is aided at lower temperatures by the formation of sulfuric acid. The mineralogies and descriptions of incrustations at fumaroles at a large number of other volcanoes from every part of the world are similar to what we have found in Central America. Thus we believe our conclusions have general applicability

Cl, F, and SO2 in Central American volcanic gases

The Cl, F, SO2 contents and Cl/F and Cl/SO4 ratios in Central American volcanic gases are examined. 103−105 tons SO2 per day are given off during eruptions and 102 when a prominent vapor cloud persists between eruptive periods. Data regarding Cl and F and SO4 from leachates, condensates, and incrustations are compared. Our data suggest circumpacific volcanoes are SO2 poor relative to Cl and may be F poor although F is higher in basaltic Central American volcanoes than others

Soil Mercury Study of Thermal Areas, Rincón de la Vieja Volcano, Costa Rica

Numerous thermal areas are found on the southwest flank of the active volcano Rincón de la Vieja, Costa Rica. These are part of a larger band of thermal areas that parallels the volcanic front for about 25 km. A total of 318 soil Hg samples were collected on the southwest flank of the volcano, predominantly at the Las Pailas hot springs. Soil Hg concentrations range from 6 to 180,000 ppb and can be divided into three populations with threshold values of 47 and 190 ppb. Aureole Hg values are widely distributed; anomalous soil Hg concentrations were found at four locations. Two-dimensional Fourier analysis of smoothed Hg values from the Las Pailas thermal area reveals a N70W trending lineament of high Hg concentration. This lineament is thought to indicate the presence of a fault along which upwelling of geothermal fluids is enhanced. The orientationof this fault coincides with the orientation of volcano alignments and structural features identified elsewhere in the region

Volcanic activity at Santiaguito volcano, Guatemala June 1968 – August 1969

Information regarding activity of Santiaguito dome, in western Guatemala, for the period June 1968–August 1969, has been derived from phots taken repeatedly at strategic locations, weekly geologic observations from a nearby lookout and ten expeditions to the mountain. Activity continues at the principal Caliente vent. Ash, bombs and gas eruptions have been interspersed with repeated extrusion and blasting away of small plug domes. At the subsidiary vent, El Brujo, dome extrusion and accompanying avalanching, so prominent in 1967–68, has declined since late 1968. The minimum volume of the El Brujo dome (formed since 1966) is estimated to be 8.5 × 106 m3

Variation in Sulfur Dioxide Emissions Related to Earth Tides, Halemaumau Crater, Kilauea Volcano, Hawaii

Variation in SO2 emissions from Halemaumau crater, Kilauea volcano, Hawaii is analyzed using a set of techniques known as exploratory data analysis. SO2 flux was monitored using a correlation spectrometer. A total of 302 measurements were made on 73 days over a 90‐day period. The mean flux was 171 t/d with a standard deviation of 52 t/d. A significant increase in flux occurs during increased seismic activity beneath the caldera. SO2 flux prior to the this change varies in a systematic way and may be related to variation in the tidal modulation envelope