Statistics for Spatial Data.

Responding to the latest developments in rock physics research, this popular reference book has been thoroughly updated while retaining its comprehensive coverage of the fundamental theory, concepts, and laboratory results. It brings together the vast literature from the field to address the relationships between geophysical observations and the underlying physical properties of Earth materials - including water, hydrocarbons, gases, minerals, rocks, ice, magma and methane hydrates. This third edition includes expanded coverage of topics such as effective medium models, viscoelasticity, attenuation, anisotropy, electrical-elastic cross relations, and highlights applications in unconventional reservoirs. Appendices have been enhanced with new materials and properties, while worked examples (supplemented by online datasets and MATLAB® codes) enable readers to implement the workflows and models in practice. This significantly revised edition will continue to be the go-to reference for students and researchers interested in rock physics, near-surface geophysics, seismology, and professionals in the oil and gas industries.

The Rock Physics Handbook

Abstract Owing to advances in microanalytical techniques over the last 15 years, there is a growing database on the volatile contents of subduction-related magmas as recorded in melt (glass) inclusions trapped in phenocrysts in volcanic rocks. Basaltic magmas from subduction zones show a wide range of water contents, ranging from as high as 6–8 to 3000 ppm, suggesting that no melt inclusions sample undegassed arc magmas. The Cl and S contents of arc basaltic magmas are greater than midocean ridge basalts, indicating that these volatiles are also recycled from subducted sediment and altered oceanic crust back into the mantle wedge. Comparison of the fluxes of volatiles subducted back into the mantle along subduction zones and returned from the mantle to the surface reservoir (crust, ocean, and atmosphere) via magmatism suggests that there is an approximate balance for structurally bound H2O and Cl. In contrast, ∼50% of subducted C appears to be returned to the deep mantle by subduction, but uncertainties are relatively large. For S, the amount returned to the surface reservoir by subduction zone magmatism is only ∼15–30% of the total amount being subducted. Dacitic and rhyolitic magmas in arcs contain 1–6 wt.% H2O, a range that overlaps considerably with the values for basaltic magmas. Either basaltic parents for these differentiated magmas are relatively H2O-poor, or intermediate to silicic arc magmas form through open-system processes involving variable amounts of crustal melting, mixing with basalt and basaltic differentiates, and fluxing of CO2-rich vapor from mafic magma recharged into silicic magma bodies. Consideration of H2O–CO2 relations and gaseous SO2 emissions for intermediate to silicic arc magmas shows that such magmas are typically vapor-saturated during crystallization in the middle to upper crust. Gas emissions thus reflect migration and accumulation of volatiles within complex open magmatic systems.

Volatiles in subduction zone magmas : concentration and fluxes based on melt inclusion and volcanic gas data

http://www.geo.mtu.edu/EHaz/ConvergentPlatesClass/wallace/Wallace_2005_SOTA.pdf

Volatiles in subduction zone magmas: concentrations and fluxes based on melt inclusion and volcanic gas data

CO2 storage in geological media: Role, means, status and barriers to deployment

Volcanic-gas studies: Methods, results, and applications

The volatile content of magma in the reservoirs of active volcanoes has an important bearing on problems of petrogenesis, magma degassing, eruption mechanisms, eruption forecasting and monitoring and the environmental impact of eruptions. Volcanic gas compositions and the S content of glasses are used to infer the volatile content and the degassing systematics of magma from the Kilauea volcano. Our results are combined with data for Kilauea's magma supply and distribution over the past 27 yr to calculate the volatile budget of the volcano.

Volatile budget of Kilauea volcano

Magmatic gas scrubbing: implications for volcano monitoring

Metal emissions from Kilauea, and a suggested revision of the estimated worldwide metal output by quiescent degassing of volcanoes

A model for the exsolution of H2O, CO2, and S from Kilauea magma as it rises from a shallow crustal reservoir predicts that vigorous exsolution occurs only after magma has ascended to shallow depths (≲ 150 m lithostatic) where pressures are <3 MPa (30 bars). Exsolved vapor at saturation (30–100 MPa) is CO2-rich (70 vol %, maximum), but H2O increases and ultimately predominates in the vapor as pressure drops. The model indicates that most H2O remains dissolved, however, down to pressures as low as 2–3 MPa (20–30 bars) rather than being exsolved abundantly below 8 MPa (80 bars) as is commonly assumed. Most CO2 is exsolved above 10 MPa, whereas most S, like H2O, is exsolved below 2–3 MPa (<100–150 m lithostatic). The critical condition for major outgassing and disruption of magma into spray is reached at 1.0–0.6 MPa (∼40–25 m lithostatic). Gas exsolution apparently continues after disruption. The total quantity of exsolved volatiles as predicted by the exsolution model agrees with that predicted by models of fire fountain dynamics. At 0.3–0.4 MPa (≲20 m lithostatic), the exsolved gases resemble volcanic gases of east rift zone eruptions and coexist with melts containing volatiles at concentrations similar to those observed in fountain spatter. Exsolution from coalesced spatter of previously disrupted melt produces residual gases that are H2O-rich and sharply depleted in CO2. The low pressures and shallow depths required for extensive exsolution imply that magma must be transported nearly to the surface before disruption, outgassing, and fountaining are possible. Therefore eruption forecasting techniques based on detection of volatiles outgassed from ascending magma may not provide useful advance warning at Kilauea and other tholeiite basalt systems.

Terrence M. Gerlach

Papers

Volcanic-gas studies: Methods, results, and applications

Volatile budget of Kilauea volcano

Magmatic gas scrubbing: implications for volcano monitoring

Metal emissions from Kilauea, and a suggested revision of the estimated worldwide metal output by quiescent degassing of volcanoes

Exsolution of H2O, CO2, and S during eruptive episodes at Kilauea Volcano, Hawaii