Pub Date : 2023-01-10DOI: 10.1146/annurev-earth-071822-100356
J. Kirchner, P. Benettin, Ilja van Meerveld
Landscapes receive water from precipitation and then transport, store, mix, and release it, both downward to streams and upward to vegetation. How they do this shapes floods, droughts, biogeochemical cycles, contaminant transport, and the health of terrestrial and aquatic ecosystems. Because many of the key processes occur invisibly in the subsurface, our conceptualization of them has often relied heavily on physical intuition. In recent decades, however, much of this intuition has been overthrown by field observations and emerging measurement methods, particularly involving isotopic tracers. Here we summarize key surprises that have transformed our understanding of hydrological processes at the scale of hillslopes and drainage basins. These surprises have forced a shift in perspective from process conceptualizations that are relatively static, homogeneous, linear, and stationary to ones that are predominantly dynamic, heterogeneous, nonlinear, and nonstationary. ▪ Surprising observations and novel measurements are transforming our understanding of the hydrological functioning of landscapes. ▪ Even during storm peaks, streamflow is composed mostly of water that has been stored in the landscape for weeks, months, or years. ▪ Streamflow and tree water uptake often originate from different subsurface storages and from different seasons’ precipitation. ▪ Stream networks dynamically extend and retract as the landscape wets and dries, and many stream reaches lose flow into underlying aquifers. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"Instructive Surprises in the Hydrological Functioning of Landscapes","authors":"J. Kirchner, P. Benettin, Ilja van Meerveld","doi":"10.1146/annurev-earth-071822-100356","DOIUrl":"https://doi.org/10.1146/annurev-earth-071822-100356","url":null,"abstract":"Landscapes receive water from precipitation and then transport, store, mix, and release it, both downward to streams and upward to vegetation. How they do this shapes floods, droughts, biogeochemical cycles, contaminant transport, and the health of terrestrial and aquatic ecosystems. Because many of the key processes occur invisibly in the subsurface, our conceptualization of them has often relied heavily on physical intuition. In recent decades, however, much of this intuition has been overthrown by field observations and emerging measurement methods, particularly involving isotopic tracers. Here we summarize key surprises that have transformed our understanding of hydrological processes at the scale of hillslopes and drainage basins. These surprises have forced a shift in perspective from process conceptualizations that are relatively static, homogeneous, linear, and stationary to ones that are predominantly dynamic, heterogeneous, nonlinear, and nonstationary. ▪ Surprising observations and novel measurements are transforming our understanding of the hydrological functioning of landscapes. ▪ Even during storm peaks, streamflow is composed mostly of water that has been stored in the landscape for weeks, months, or years. ▪ Streamflow and tree water uptake often originate from different subsurface storages and from different seasons’ precipitation. ▪ Stream networks dynamically extend and retract as the landscape wets and dries, and many stream reaches lose flow into underlying aquifers. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":null,"pages":null},"PeriodicalIF":14.9,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75136093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-10DOI: 10.1146/annurev-earth-031621-071250
M. Hodgskiss, P. Crockford, A. Turchyn
The early to mid-Paleoproterozoic Lomagundi-Jatuli Excursion (LJE) is ostensibly the largest magnitude (approximately +5 to +30‰), longest duration (ca. 130–250 million years) positive carbon isotope excursion measured in carbonate rocks in Earth history. The LJE has been attributed to large nutrient fluxes, an increase in the size of the biosphere, a reorganization of the global carbon cycle, and oxygenation of the atmosphere. However, significant debate remains about its genesis, synchroneity, global-versus-local extent, and role in atmospheric oxygenation. Here we review existing models and mechanisms suggested for the LJE and analyze a compilation of ∼9,400 δ13C and associated contextual data. These data call into question the interpretation of the LJE as a globally synchronous carbon isotope excursion and suggest that any model for the LJE must account for both the absence of a clearly defined initiation and termination of the excursion and a facies-dependent expression of 13C-enrichment. ▪ The Lomagundi-Jatuli Excursion (LJE) continues to challenge current understandings of the carbon cycle. ▪ Understanding this excursion is critical for reconstructing biogeochemical cycles and atmospheric oxygenation through Earth history. ▪ Some evidence indicates local rather than global changes in δ13CDIC and raises the possibility of asynchronous, local excursions. ▪ Resolving whether the LJE was globally synchronous or asynchronous is essential for discriminating between different models. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"Deconstructing the Lomagundi-Jatuli Carbon Isotope Excursion","authors":"M. Hodgskiss, P. Crockford, A. Turchyn","doi":"10.1146/annurev-earth-031621-071250","DOIUrl":"https://doi.org/10.1146/annurev-earth-031621-071250","url":null,"abstract":"The early to mid-Paleoproterozoic Lomagundi-Jatuli Excursion (LJE) is ostensibly the largest magnitude (approximately +5 to +30‰), longest duration (ca. 130–250 million years) positive carbon isotope excursion measured in carbonate rocks in Earth history. The LJE has been attributed to large nutrient fluxes, an increase in the size of the biosphere, a reorganization of the global carbon cycle, and oxygenation of the atmosphere. However, significant debate remains about its genesis, synchroneity, global-versus-local extent, and role in atmospheric oxygenation. Here we review existing models and mechanisms suggested for the LJE and analyze a compilation of ∼9,400 δ13C and associated contextual data. These data call into question the interpretation of the LJE as a globally synchronous carbon isotope excursion and suggest that any model for the LJE must account for both the absence of a clearly defined initiation and termination of the excursion and a facies-dependent expression of 13C-enrichment. ▪ The Lomagundi-Jatuli Excursion (LJE) continues to challenge current understandings of the carbon cycle. ▪ Understanding this excursion is critical for reconstructing biogeochemical cycles and atmospheric oxygenation through Earth history. ▪ Some evidence indicates local rather than global changes in δ13CDIC and raises the possibility of asynchronous, local excursions. ▪ Resolving whether the LJE was globally synchronous or asynchronous is essential for discriminating between different models. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":null,"pages":null},"PeriodicalIF":14.9,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82867176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-06DOI: 10.1146/annurev-earth-032320-110916
R. Alley, K. Cuffey, J. Bassis, K. Alley, S. Wang, B. R. Parizek, S. Anandakrishnan, K. Christianson, R. DeConto
Uncertainty about sea-level rise is dominated by uncertainty about iceberg calving, mass loss from glaciers or ice sheets by fracturing. Review of the rapidly growing calving literature leads to a few overarching hypotheses. Almost all calving occurs near or just downglacier of a location where ice flows into an environment more favorable for calving, so the calving rate is controlled primarily by flow to the ice margin rather than by fracturing. Calving can be classified into five regimes, which tend to be persistent, predictable, and insensitive to small perturbations in flow velocity, ice characteristics, or environmental forcing; these regimes can be studied instrumentally. Sufficiently large perturbations may cause sometimes-rapid transitions between regimes or between calving and noncalving behavior, during which fracturing may control the rate of calving. Regime transitions underlie the largest uncertainties in sea-level rise projections, but with few, important exceptions, have not been observed instrumentally. This is especially true of the most important regime transitions for sea-level rise. Process-based models informed by studies of ongoing calving, and assimilation of deep-time paleoclimatic data, may help reduce uncertainties about regime transitions. Failure to include calving accurately in predictive models could lead to large underestimates of warming-induced sea-level rise. ▪ Iceberg calving, the breakage of ice from glaciers and ice sheets, affects sea level and many other environmental issues. ▪ Modern rates of iceberg calving usually are controlled by the rate of ice flow past restraining points, not by the brittle calving processes. ▪ Calving can be classified into five regimes, which are persistent, predictable, and insensitive to small perturbations. ▪ Transitions between calving regimes are especially important and with warming might cause faster sea-level rise than generally projected. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"Iceberg Calving: Regimes and Transitions","authors":"R. Alley, K. Cuffey, J. Bassis, K. Alley, S. Wang, B. R. Parizek, S. Anandakrishnan, K. Christianson, R. DeConto","doi":"10.1146/annurev-earth-032320-110916","DOIUrl":"https://doi.org/10.1146/annurev-earth-032320-110916","url":null,"abstract":"Uncertainty about sea-level rise is dominated by uncertainty about iceberg calving, mass loss from glaciers or ice sheets by fracturing. Review of the rapidly growing calving literature leads to a few overarching hypotheses. Almost all calving occurs near or just downglacier of a location where ice flows into an environment more favorable for calving, so the calving rate is controlled primarily by flow to the ice margin rather than by fracturing. Calving can be classified into five regimes, which tend to be persistent, predictable, and insensitive to small perturbations in flow velocity, ice characteristics, or environmental forcing; these regimes can be studied instrumentally. Sufficiently large perturbations may cause sometimes-rapid transitions between regimes or between calving and noncalving behavior, during which fracturing may control the rate of calving. Regime transitions underlie the largest uncertainties in sea-level rise projections, but with few, important exceptions, have not been observed instrumentally. This is especially true of the most important regime transitions for sea-level rise. Process-based models informed by studies of ongoing calving, and assimilation of deep-time paleoclimatic data, may help reduce uncertainties about regime transitions. Failure to include calving accurately in predictive models could lead to large underestimates of warming-induced sea-level rise. ▪ Iceberg calving, the breakage of ice from glaciers and ice sheets, affects sea level and many other environmental issues. ▪ Modern rates of iceberg calving usually are controlled by the rate of ice flow past restraining points, not by the brittle calving processes. ▪ Calving can be classified into five regimes, which are persistent, predictable, and insensitive to small perturbations. ▪ Transitions between calving regimes are especially important and with warming might cause faster sea-level rise than generally projected. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":null,"pages":null},"PeriodicalIF":14.9,"publicationDate":"2023-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90387401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-06DOI: 10.1146/annurev-earth-032320-095425
Benjamin J. W. Mills, Alexander J. Krause, I. Jarvis, B. Cramer
An oxygen-rich atmosphere is essential for complex animals. The early Earth had an anoxic atmosphere, and understanding the rise and maintenance of high O2 levels is critical for investigating what drove our own evolution and for assessing the likely habitability of exoplanets. A growing number of techniques aim to reproduce changes in O2 levels over the Phanerozoic Eon (the past 539 million years). We assess these methods and attempt to draw the reliable techniques together to form a consensus Phanerozoic O2 curve. We conclude that O2 probably made up around 5–10% of the atmosphere during the Cambrian and rose in pulses to ∼15–20% in the Devonian, reaching a further peak of greater than 25% in the Permo-Carboniferous before declining toward the present day. Evolutionary radiations in the Cambrian and Ordovician appear consistent with an oxygen driver, and the Devonian “Age of the Fishes” coincides with oxygen rising above 15% atm. ▪ An oxygen-rich atmosphere is essential for complex animals such as humans. ▪ We review the methods for reconstructing past variation in oxygen levels over the past 539 million years (the Phanerozoic Eon). ▪ We produce a consensus plot of the most likely evolution of atmospheric oxygen levels. ▪ Evolutionary radiations in the Cambrian, Ordovician, and Devonian periods may be linked to rises in oxygen concentration. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"Evolution of Atmospheric O2 Through the Phanerozoic, Revisited","authors":"Benjamin J. W. Mills, Alexander J. Krause, I. Jarvis, B. Cramer","doi":"10.1146/annurev-earth-032320-095425","DOIUrl":"https://doi.org/10.1146/annurev-earth-032320-095425","url":null,"abstract":"An oxygen-rich atmosphere is essential for complex animals. The early Earth had an anoxic atmosphere, and understanding the rise and maintenance of high O2 levels is critical for investigating what drove our own evolution and for assessing the likely habitability of exoplanets. A growing number of techniques aim to reproduce changes in O2 levels over the Phanerozoic Eon (the past 539 million years). We assess these methods and attempt to draw the reliable techniques together to form a consensus Phanerozoic O2 curve. We conclude that O2 probably made up around 5–10% of the atmosphere during the Cambrian and rose in pulses to ∼15–20% in the Devonian, reaching a further peak of greater than 25% in the Permo-Carboniferous before declining toward the present day. Evolutionary radiations in the Cambrian and Ordovician appear consistent with an oxygen driver, and the Devonian “Age of the Fishes” coincides with oxygen rising above 15% atm. ▪ An oxygen-rich atmosphere is essential for complex animals such as humans. ▪ We review the methods for reconstructing past variation in oxygen levels over the past 539 million years (the Phanerozoic Eon). ▪ We produce a consensus plot of the most likely evolution of atmospheric oxygen levels. ▪ Evolutionary radiations in the Cambrian, Ordovician, and Devonian periods may be linked to rises in oxygen concentration. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":null,"pages":null},"PeriodicalIF":14.9,"publicationDate":"2023-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89497051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-06DOI: 10.1146/annurev-earth-071822-100304
M. Cocco, S. Aretusini, C. Cornelio, S. Nielsen, E. Spagnuolo, E. Tinti, G. Di Toro
Large seismogenic faults consist of approximately meter-thick fault cores surrounded by hundreds of meter-thick damage zones. Earthquakes are generated by rupture propagation and slip within fault cores and dissipate the stored elastic strain energy in fracture and frictional processes in the fault zone and in radiated seismic waves. Understanding this energy partitioning is fundamental in earthquake mechanics to explain fault dynamic weakening and causative rupture processes operating over different spatial and temporal scales. The energy dissipated in the earthquake rupture propagation along a fault is called fracture energy or breakdown work. Here we review fracture energy estimates from seismological, modeling, geological, and experimental studies and show that fracture energy scales with fault slip. We conclude that although material-dependent constant fracture energies are important at the microscale for fracturing grains of the fault zone, they are negligible with respect to the macroscale processes governing rupture propagation on natural faults. ▪ Earthquake ruptures propagate on geological faults and dissipate energy in fracture and frictional processes from micro- (less than a millimeter) to macroscale (centimeters to kilometers). ▪ The energy dissipated in earthquake rupture propagation is called fracture energy ( G) or breakdown work ( Wb) and scales with coseismic slip. ▪ For earthquake ruptures in natural faults, the estimates of G and Wb are consistent with a macroscale description of causative processes. ▪ The energy budget of an earthquake remains controversial, and contributions from different disciplines are required to unravel this issue. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"Fracture Energy and Breakdown Work During Earthquakes","authors":"M. Cocco, S. Aretusini, C. Cornelio, S. Nielsen, E. Spagnuolo, E. Tinti, G. Di Toro","doi":"10.1146/annurev-earth-071822-100304","DOIUrl":"https://doi.org/10.1146/annurev-earth-071822-100304","url":null,"abstract":"Large seismogenic faults consist of approximately meter-thick fault cores surrounded by hundreds of meter-thick damage zones. Earthquakes are generated by rupture propagation and slip within fault cores and dissipate the stored elastic strain energy in fracture and frictional processes in the fault zone and in radiated seismic waves. Understanding this energy partitioning is fundamental in earthquake mechanics to explain fault dynamic weakening and causative rupture processes operating over different spatial and temporal scales. The energy dissipated in the earthquake rupture propagation along a fault is called fracture energy or breakdown work. Here we review fracture energy estimates from seismological, modeling, geological, and experimental studies and show that fracture energy scales with fault slip. We conclude that although material-dependent constant fracture energies are important at the microscale for fracturing grains of the fault zone, they are negligible with respect to the macroscale processes governing rupture propagation on natural faults. ▪ Earthquake ruptures propagate on geological faults and dissipate energy in fracture and frictional processes from micro- (less than a millimeter) to macroscale (centimeters to kilometers). ▪ The energy dissipated in earthquake rupture propagation is called fracture energy ( G) or breakdown work ( Wb) and scales with coseismic slip. ▪ For earthquake ruptures in natural faults, the estimates of G and Wb are consistent with a macroscale description of causative processes. ▪ The energy budget of an earthquake remains controversial, and contributions from different disciplines are required to unravel this issue. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":null,"pages":null},"PeriodicalIF":14.9,"publicationDate":"2023-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89446970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-28DOI: 10.1146/annurev-earth-031621-080308
J. Gardner, F. Wadsworth, T. Carley, E. Llewellin, H. Kusumaatmaja, D. Sahagian
Volcanic eruptions are driven by bubbles that form when volatile species exsolve from magma. The conditions under which bubbles form depend mainly on magma composition, volatile concentration, presence of crystals, and magma decompression rate. These are all predicated on the mechanism by which volatiles exsolve from the melt to form bubbles. We critically review the known or inferred mechanisms of bubble formation in magmas: homogeneous nucleation, heterogeneous nucleation on crystal surfaces, and spontaneous phase separation (spinodal decomposition). We propose a general approach for calculating bubble nucleation rates as the sum of the contributions from homogeneous and heterogeneous nucleation, suggesting that nucleation may not be limited to a single mechanism prior to eruption. We identify three major challenges in which further experimental, analytical, and theoretical work is required to permit the development of a general model for bubble formation under natural eruption conditions. ▪ We review the mechanisms of bubble formation in magma and summarize the conditions under which the various mechanisms are understood to operate. ▪ Bubble formation mechanisms may evolve throughout magma ascent as conditions change such that bubbles may form simultaneously and sequentially via more than one mechanism. ▪ Contributions from both homogeneous nucleation and heterogeneous nucleation on multiphase crystal phases can be captured via a single equation. ▪ Future work should focus on constraining macroscopic surface tension, characterizing the microphysics, and developing a general framework for modeling bubble formation, via all mechanisms, over natural magma ascent pathways. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"Bubble Formation in Magma","authors":"J. Gardner, F. Wadsworth, T. Carley, E. Llewellin, H. Kusumaatmaja, D. Sahagian","doi":"10.1146/annurev-earth-031621-080308","DOIUrl":"https://doi.org/10.1146/annurev-earth-031621-080308","url":null,"abstract":"Volcanic eruptions are driven by bubbles that form when volatile species exsolve from magma. The conditions under which bubbles form depend mainly on magma composition, volatile concentration, presence of crystals, and magma decompression rate. These are all predicated on the mechanism by which volatiles exsolve from the melt to form bubbles. We critically review the known or inferred mechanisms of bubble formation in magmas: homogeneous nucleation, heterogeneous nucleation on crystal surfaces, and spontaneous phase separation (spinodal decomposition). We propose a general approach for calculating bubble nucleation rates as the sum of the contributions from homogeneous and heterogeneous nucleation, suggesting that nucleation may not be limited to a single mechanism prior to eruption. We identify three major challenges in which further experimental, analytical, and theoretical work is required to permit the development of a general model for bubble formation under natural eruption conditions. ▪ We review the mechanisms of bubble formation in magma and summarize the conditions under which the various mechanisms are understood to operate. ▪ Bubble formation mechanisms may evolve throughout magma ascent as conditions change such that bubbles may form simultaneously and sequentially via more than one mechanism. ▪ Contributions from both homogeneous nucleation and heterogeneous nucleation on multiphase crystal phases can be captured via a single equation. ▪ Future work should focus on constraining macroscopic surface tension, characterizing the microphysics, and developing a general framework for modeling bubble formation, via all mechanisms, over natural magma ascent pathways. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":null,"pages":null},"PeriodicalIF":14.9,"publicationDate":"2022-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73547292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-21DOI: 10.1146/annurev-earth-071822-100323
S. Mousavi, G. Beroza
Machine learning (ML) is a collection of methods used to develop understanding and predictive capability by learning relationships embedded in data. ML methods are becoming the dominant approaches for many tasks in seismology. ML and data mining techniques can significantly improve our capability for seismic data processing. In this review we provide a comprehensive overview of ML applications in earthquake seismology, discuss progress and challenges, and offer suggestions for future work. ▪ Conceptual, algorithmic, and computational advances have enabled rapid progress in the development of machine learning approaches to earthquake seismology. ▪ The impact of that progress is most clearly evident in earthquake monitoring and is leading to a new generation of much more comprehensive earthquake catalogs. ▪ Application of unsupervised approaches for exploratory analysis of these high-dimensional catalogs may reveal new understanding of seismicity. ▪ Machine learning methods are proving to be effective across a broad range of other seismological tasks, but systematic benchmarking through open source frameworks and benchmark data sets are important to ensure continuing progress. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"Machine Learning in Earthquake Seismology","authors":"S. Mousavi, G. Beroza","doi":"10.1146/annurev-earth-071822-100323","DOIUrl":"https://doi.org/10.1146/annurev-earth-071822-100323","url":null,"abstract":"Machine learning (ML) is a collection of methods used to develop understanding and predictive capability by learning relationships embedded in data. ML methods are becoming the dominant approaches for many tasks in seismology. ML and data mining techniques can significantly improve our capability for seismic data processing. In this review we provide a comprehensive overview of ML applications in earthquake seismology, discuss progress and challenges, and offer suggestions for future work. ▪ Conceptual, algorithmic, and computational advances have enabled rapid progress in the development of machine learning approaches to earthquake seismology. ▪ The impact of that progress is most clearly evident in earthquake monitoring and is leading to a new generation of much more comprehensive earthquake catalogs. ▪ Application of unsupervised approaches for exploratory analysis of these high-dimensional catalogs may reveal new understanding of seismicity. ▪ Machine learning methods are proving to be effective across a broad range of other seismological tasks, but systematic benchmarking through open source frameworks and benchmark data sets are important to ensure continuing progress. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":null,"pages":null},"PeriodicalIF":14.9,"publicationDate":"2022-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77367555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-02DOI: 10.1146/annurev-earth-031621-060538
L. Borg, R. Carlson
Defining the age of the Moon has proven to be an elusive task because it requires reliably dating lunar samples using radiometric isotopic systems that record fractionation of parent and daughter elements during events that are petrologically associated with planet formation. Crystallization of the magma ocean is the only event that unambiguously meets this criterion because it probably occurred within tens of millions of years of Moon formation. There are three dateable crystallization products of the magma ocean: mafic mantle cumulates, felsic crustal cumulates, and late-stage crystallization products known as urKREEP (uniform residuum K, rare earth elements, and P). Although ages for these materials in the literature span 200 million years, there is a preponderance of reliable ages around 4.35 billion years recorded in all three lunar rock types. This age is also observed in many secondary crustal rocks, indicating that they were produced contemporaneously (within uncertainty of the ages), possibly during crystallization and overturn of the magma ocean. ▪ The duration of planet formation is key information in understanding the mechanisms by which the terrestrial planets formed. ▪ Ages of the oldest lunar rocks range widely, reflecting either the duration of Moon formation or disturbed ages caused by impact metamorphism. ▪ Ages determined for compositionally distinct crust and mantle materials produced by lunar magma ocean differentiation cluster near 4.35 Gyr. ▪ The repeated occurrence of 4.35 Gyr ages implies that Moon formation occurred late in Solar System history, likely by giant impact into Earth. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Pub Date : 2022-11-01DOI: 10.1146/annurev-earth-080322-082343
E. Atekwana
I describe my career journey from a young girl in Cameroon, West Africa, to a trailblazing geophysicist to my current role as dean. I chronicle my time as a student, the transition to being an early career faculty, launching my research career, and ultimately finding my way to administration. Along the way I helped pioneer biogeophysics as a subdiscipline in geophysics while simultaneously maintaining an international research program in continental rift tectonics. I also describe the many intersectionalities in my life including being the first Black woman in many spaces, being a champion for student success, developing a diverse talent pipeline by enhancing diversity in the geosciences, and navigating academic job searches as part of a dual-career couple. Finally, I acknowledge all those who helped shape my career including the many students I had the opportunity to mentor. ▪ Many underrepresented minority geoscientists lack the social capital and professional networks critical for their success. ▪ Geoscience departments must be intentional and deliberate in promoting and ensuring more inclusive workplace environments. ▪ Dual-career couples remain a major challenge, impacting retention and recruitment of top talent; universities should provide resources to alleviate this challenge. ▪ Biogeophysics has untapped potential for advancing understanding of subsurface biogeochemical processes and the search for life in extreme environments. ▪ To date, considerable speculation remains regarding the fundamental geodynamic processes that initiate and sustain the evolution of magma-deficient rifts. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Pub Date : 2022-05-31DOI: 10.1146/annurev-earth-070921-062047
M. Edmonds, E. Mason, Olivia R. Hogg
Volcanoes play a key role in the cycling of volatile metals (e.g., chalcophile elements such as Tl, Pb, and Cu and metalloids such as As, Te, and Se) on our planet. Volatile metals and metalloids are outgassed by active volcanoes, forming particulate volcanic plumes that deliver them in reactive form to the environment, where they may be nutrients (e.g., Cu and Zn) or pollutants (e.g., Hg, As, Pb). Volcanic outgassing rates of these elements compare to those associated with building ore deposits in the crust and to anthropogenic emission rates. There are distinct compositional differences between volcanic plumes in different tectonic settings, related to the enrichment of arc magmas in metals transported in slab fluids, metal speciation, and partitioning between silicate melt, vapor, and magmatic sulfide. Volcanic gases have compositions similar to those of quartz-hosted fluid inclusions found in mineralized granites, albeit with a lower density and salinity. Volatile volcanic metals are transported as soluble aerosols in volcanic plumes and may persist for hundreds of kilometers in the troposphere. Volcanic metal chloride aerosols in tropospheric volcanic plumes at high latitudes are recorded in ice cores. ▪ Volcanoes emit significant fluxes of volatile trace metals such as Cu, Tl, and Pb, as gases and particulates, to the surface environment. ▪ There is a distinct metal compositional fingerprint in volcanic and hydrothermal plumes at subduction and hotspot volcanoes and mid-ocean ridges, controlled by magma and fluid chemistry. ▪ Volcanic gases are the less saline equivalent of the fluids forming economic porphyry deposits of chalcophile metals (e.g., Cu) in the crust. ▪ The metals in tropospheric volcanic plumes may be rained out near the vent, but in dry environments they may persist for thousands of kilometers and be deposited in ice cores.
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