Running Head: Rock uplift west of the Fairweather fault, AlaskaR.C. Witter1, H.M. Kelsey2, R.O. Lease1, A.M. Bender1, K.M. Scharer3, and P.J. Haeussler1, and D.S. Brothers41U.S. Geological Survey Alaska Science Center, Anchorage, AK, USA2Department of Geology, Cal Poly Humboldt, Arcata, CA, USA3U.S. Geological Survey Earthquake Science Center, Pasadena, CA, USA4U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA, USAAbstract [286/300 words]Contraction along the Yakutat-(Pacific)-North America plate boundary drives extreme rock uplift along Earth’s fastest slipping (≥49 mm/yr) ocean-continent transform fault, the Fairweather fault. Between Icy Point and Lituya Bay, the near-vertical Fairweather fault focuses rock uplift and rapid right-lateral slip by accommodating both vertical and fault-parallel strain during ruptures with a substantial vertical-slip component and separate, predominantly strike-slip events. We use 1.0 m resolution digital elevation models and offshore seismic reflection profiles to map active faults, uplifted marine and fluvial terraces, and document past reverse fault earthquakes with maximum 3–5 m of coseismic uplift per event. Radiocarbon and luminescence dating provide timing to estimate 4.6–9.0 mm/yr Holocene rock uplift rates, which match 5–10 km/Myr Quaternary exhumation rates estimated from thermochronometry. These unusually high uplift rates result from plate-boundary strain that is partitioned onto reverse faults that form, together with the steeply dipping Fairweather fault, a 10-km-wide, asymmetric, positive flower structure along a 20°, ~30-km-long restraining double bend in the Fairweather fault. The principal reverse fault in the flower structure is the offshore, blind Icy Point-Lituya Bay fault, which ruptures no more than every 460–1040 years evidenced by uplifted Holocene marine shorelines. Evaluated over a range of dips, the uplift on this reverse fault implies maximum 3.1–10 m dip slip per event and estimated earthquake magnitudes of Mw 7.0–7.5. Our model implies oblique slip on the Fairweather fault at seismogenic depths with and without co-rupture on the reverse fault. Oblique slip on the Fairweather fault is evident where it vertically offsets fluvial and marine terraces by >25 m, strikes >20° west of plate boundary motion, juxtaposes near-surface rocks of different strength, and where the Yakutat block collides obliquely into North America.

Convergent orogens are typically linear with laterally continuous, orogen-parallel folds and thrusts. Over the years, geoscience research has revealed evidence for important orthogonal/cross structures as well as lateral heterogeneity in deformation style, igneous activity, metamorphic grade, geomorphology, and seismic activity. To assess the occurrence, causal mechanisms, and implications of these lateral heterogeneities, a selection of convergent orogens, with different tectonic settings and history are reviewed. The Appalachians, the North American Cordillera, the Alps, the Himalayas, the Zagros, the Andes, and several other belts all exhibit a degree of lateral heterogeneity. Major factors driving the lateral heterogeneity and/or cross structures include the pre-existing deformational history of the cratonic blocks involved, lateral change in lithology of crustal rocks, variations in crustal/lithospheric rheologic properties, or changes in plate kinematics. The Appalachian orogenic front mimics the Iapetan rift margin. Pre-existing basement structures have control on pre- and syn-orogenic sedimentation, which subsequently impacts how an orogenic wedge evolves. A thicker sedimentary column generally evolves into a salient (as opposed to a recess), which is further enhanced by the presence of weak horizons as seen in the Zagros and the Cordillera. Lateral variation in sedimentary facies also creates changes in thrust-ramp geometry. During orogenic contraction, inherited basement structures can be preferentially reactivated based on their orientation. Several cross faults in the Himalayas spatially coincide with orogen-perpendicular, lower plate, basement structures. In a similar way, oceanic subducting plate physiography can also influence deformation in the overriding plate. Along-strike variations in subduction dynamics have been reflected in the Andean deformation. Orogenic extension in the Alps has been accompanied by a system of orogen-parallel strike slip faults and extensional cross faults. It is evident that lateral heterogeneities can form crucial control on the evolution of orogenic belts and can influence seismic rupture patterns, resource occurrence, and landslide-related natural hazards.

A thermodynamic model to calculate the “Sulfide Content at Sulfide Saturation” or SCSS of basaltic and intermediate composition silicate melts has been built from four independently measurable thermodynamic entities, namely the standard state Gibbs free energy of the saturation reaction, the “sulfide capacity”, and the activities of FeO in the silicate melt and of FeS in the coexisting sulfide: ln [S2-]SCSS = ∆G(FeO-FeS)/RT + ln C(S2- )- ln a(FeO)(sil melt) + ln a(FeS)sulf The model was calibrated for silicate melts of basic and intermediate composition from published experimental results as a function of temperature, silicate melt composition, and sulfide matte composition in the system Fe-Ni-Cu-S-O at 1 bar. The likely effects of pressure and H2O content on SCSS were included in an exploratory way. The model was tuned against the large dataset of S contents in OFB glasses of Jenner and O’Neill (2012), giving it a precision comparable to that of the S analyses themselves, which is ~ 5%. All but 3% the OFB glasses were found to be sulfide saturated within uncertainty; these 3% have lost S by devolatization, revealed by their low S/Se. Applying the model to other OFB datasets suggests sulfide saturation is ubiquitous, including olivine-hosted melt inclusions proposed previously to be sulfide undersaturated. The sulfur fugacity (fS2) of undegassed Ocean Floor Basalts varies proportionally to fO2, with log10fS2 typically within the range -0.6 to +0.4.

Intraslab earthquakes do not produce primary paleoseismic evidence at the Earth’s surface, making efforts to develop an event chronology challenging. However, the strong ground motion from intraslab events may initiate gravity-driven turbidity flows in subaqueous basins; the resulting deposits (turbidites) can provide a paleoseismic proxy if the conditions that initiate these flows are known. To better constrain the initiating conditions, we use two recent intraslab earthquakes in southcentral Alaska, the Mw 7.1 November 30, 2018, Anchorage and the Mw 7.1 January 24, 2016, Iniskin earthquakes, as calibration events. Through a multi-lake investigation spanning a range of shaking intensities and based on a combined geological and geophysical dataset, we document the occurrence, or absence, of earthquake-generated turbidity flows from these two earthquakes. The 2018 and 2016 earthquakes are recorded by centimeter-scale turbidites that can be differentiated from climatically generated deposits, as well as other seismic sources (i.e., the 1964 Alaska megathrust earthquake) based on deposit thickness, sedimentological properties, and deposit age. We show that a Modified Mercalli Intensity (MMI) of ~V-V1/2 is the minimum shaking intensity required to generate localized sediment remobilization from deltaic slopes, and a MMI of ~V1/2 is required to produce a deposit of sufficient thickness that a seismic origin can be confidently assigned. Deltaic slopes are the major source of remobilized sediment that record the 2018 and 2016 events, however sediment from non-tributary sourced basin slopes may become remobilized in steep-sloped, high sedimentation areas, and under elevated shaking intensity. The documentation of seismically generated deposits in quick succession (~2 years) with diagnostic features that can be assigned to the seismic source highlights the utility of using recent earthquakes as calibration events to investigate the subaqueous response to strong ground motion. 

Preface Many physical processes that influence Earth's climate and weather occur on spatial (temporal) scales smaller (shorter) than typical grid sizes (time steps) of general circulation models, and thus must be parameterized. Computer models are essential tools for understanding atmospheric phenomena and for making accurate predictions of any changes in the Earth's climate, weather, and resources of renewable energy resulting from anthropogenic activities that generate greenhouse gases and particulates into the atmosphere. This book focuses on the atmospheric subgrid processes ─ collectively called fast physics ─by reviewing and synthesizing relevant physical understanding, parameterization developments, various measurement technologies, and model evaluation framework. The publication is divided into three parts, containing seventeen chapters (Chapters 2-17) to reflect and synthesize the multiple aspects involved. The first chapter briefly introduces the historical development of fast physics parameterizations and the involved complexities; the last chapter summarizes emerging challenges, new opportunities and future research directions. Part I deals with major subgrid processes, with eight chapters (Chapters 2-9) each covering different processes more or less in the conventional compartmentalized format with an emphasis on individual processes, including but, not limited to radiative transfer, aerosols, and aerosol direct & indirect effects, entrainment-mixing processes, their microphysical influences, convection & convective clouds, stratiform clouds such as stratus and stratocumulus clouds, planetary boundary layer processes, land surface and interactions with atmosphere, and gravity waves. On top of the conventional treatments, some promising ideas/approaches have recently emerged to unify the treatment of individual processes and thus allows for consideration of process interactions. Part II is devoted to such unifying efforts, with four chapters (Chapters 10-13) covering four different endeavors: the unifying parameterizations based on assumed probability density functions; the EDMF approach that combines the Eddy Diffusivity and Mass Flux approaches to unify turbulence and convection; application of machine learning techniques; and innovative top-down attempts that consider the involved totality by borrowing ideas from systems theory, statistical physics, and non-linear sciences. Part III (Chapters 14-17) is devoted to assessments, model evaluation, and model-measurement integration, with four chapters that focus on satellite and airborne remote sensing measurements, surface-based remote sensing measurements, in-situ and laboratory measurements, and model evaluation, and model-measurement integration, respectively.

This introductory chapter discusses the atmospheric subgrid processes ─ collectively called "fast 11 physics" or "fast processes", and their parameterizations in large scale atmospheric models. It 12 presents a brief historical progression of the parameterization of fast processes in numerical 13 models. Despite great efforts and notable advances in understanding, progress in improving fast 14 physics parameterizations has been frustratingly slow, the underlying reasons for which are 15 explored. To guide readers, this chapter describes the main objectives and scope of this book and 16 summarizes each chapter. 

With wildfires increasing in activity in the Western United States and around the world, there is an immediate need to understand the toxic effects of the smoke. This chapter will provide a background of toxicology and apply principle concepts such as dose, duration and frequency to help define the potential effects of smoke exposure. Characteristics that influence toxicity will be discussed, which include particle size, source and temperature and the mixture of chemical constituents. An overview of the routes of exposure, mechanisms of action, toxicokinetics and the role of the immune system will all be covered. The importance and mutual benefits of in vitro, ex vivo and in vivo studies will be discussed. Finally, the chapter concludes by outlining knowledge gaps and research needs.

The Gulf of Mexico is a prolific petroleum basin with more than a century-long exploration history. Tectonic models proposed for the basin vary dramatically in many aspects, ranging from the pre-rift locations of the crustal blocks, the timing of the break-up to even the order of tectonic events. The reason for these disagreements is in a thick and complex overburden that obscures seismic imaging of crustal structures. To overcome that, we integrated seismic data with gravity and magnetic fields to determine the crustal architecture in different parts of the basin, as well as to map the location of the key tectonic features. The subsequent spatial analysis of potential fields allowed us to trace the tectonic structures outside of seismic coverage. As a result, a set of new geological constraints was derived including the Triassic rifts, regions of Seaward Dipping Reflectors (SDR), and Jurassic pre-salt sedimentary basins in the eastern Gulf of Mexico and along the Yucatan margin, and two distinct crustal zones in the oceanic domain. We ensure the pre-breakup alignment of the crustal blocks based on the mapped geological features on the conjugate margins. Our tectonic reconstruction takes into account an apparent temporal variability of the magmatic regime during basin formation that ranged from CAMP (~200 Ma) to an ultra-slow amagmatic spreading during the initial stage of the GoM opening (~ 165 Ma). Our reconstruction also includes a major ridge reorganization (~ 152 Ma) associated with increased magmatic supply. This second phase of oceanic spreading ceased at early Cretaceous (~ 135 Ma) based on published correlation analysis of seismic and well data. Overall, the tectonic reconstruction presented here takes into account previously known and newly derived geological constraints and integrates various geophysical datasets, namely seismic, gravity, and magnetics.

Experiment and observation have established the centrality of oxygen fugacity (fO2) to determining the course of igneous differentiation, and so the development and application of oxybarometers have proliferated for more than half a century. The compositions of mineral, melt, and vapor phases determine the fO2 that rocks record, and the activity models that underpin calculation of fO2 from phase compositions have evolved with time. Likewise, analytical method development has made new sample categories available to oxybarometric interrogation. Here we compile published analytical data from lithologies that constrain fO2 (n=860 volcanic rocks - lavas and tephras and n=326 mantle lithologies- the majority peridotites) from ridges, back-arc basins, forearcs, arcs, and plumes. Because calculated fO2 varies with choice of activity model, we re-calculate fO2 for each dataset from compositional data, applying the same set of activity models and methodologies for each data type. Additionally, we compile trace element concentrations (e.g. vanadium) which serve as an additional fO2-proxy. The compiled data show that, on average, volcanic rocks and mantle rocks from the same tectonic setting yield similar fO2s, but mantle lithologies span a much larger range in fO2 than volcanics. Multiple Fe-based oxybarometric methods and vanadium partitioning vary with statistical significance as a function of tectonic setting, with fO2 ridges < back arcs < arcs. Plume lithologies are more nuanced to interpret, but indicate fO2s  ridges. We discuss the processes that may shift fO2 after melts and mantle lithologies physically separate from one another. We show that the effects of crystal fractionation and degassing on the fO2 of volcanics are smaller than the differences in fO2 between tectonic settings and that effects of subsolidus metamorphism on the fO2 values recorded by mantle lithologies remain poorly understood. Finally, we lay out challenges and opportunities for future inquiry.

This chapter discusses the sounds emitted by gas bubbles when they are generated underwater. Here we define bubbles to be volumes of gas, surrounded by liquid (here, taken to be water), having surface tension forces (the so-called Laplace pressure) generated by a single wall, and so are distinguished from the soap bubbles familiar in children’s games, where the volume of gas is surrounded by two gas/liquid boundaries1. In comparison with other acoustic sources, such as marine mammals, ships and tectonic events, a single bubble may seem insignificant. Indeed, without ideal conditions it can be difficult to observe the sound of a single bubble from a distance of more than a few tens of centimetres. However, natural processes rarely produce single bubbles, and in fact can generate them in their millions at which point the sound generation is significant. With the formation of bubbles as a result of gas seeps, rainfall and breaking waves being a major component of ambient noise in the marine environment and can even alter the propagation of sound waves from other sources. This chapter focuses on the passive emissions of bubbles as they are formed, released, or injected into water, and here the volume pulsations are linear. In this chapter we will discuss the mechanics behind an individual bubble’s acoustic signature, in particular the Minnaert equation and other relevant properties, before discussing the formation of bubbles from subsurface gas migration, rainfall and wave action, characterizing the acoustic nature of each process. The primary focus will be on the sound resulting from bubble generation from each of these sources. A number of different units are used to define each acoustic source, while this may appear confusing and make direct comparison difficult, this is done to be consistent with the literature. The topics covered here are broad, so the approach taken is to summarise the key principles and state of the field, while providing substantial linkage to the literature.

The mixing and mingling of magmas of different compositions are important geological processes. They produce various distinctive textures and geochemical signals in both plutonic and volcanic rocks and have implications for eruption triggering. Both processes are widely studied, with prior work focusing on field and textural observations, geochemical analysis of samples, theoretical and numerical modelling, and experiments. However, despite the vast amount of existing literature, there remain numerous unresolved questions. In particular, how does the presence of crystals and exsolved volatiles control the dynamics of mixing and mingling? Furthermore, to what extent can this dependence be parameterised through the effect of crystallinity and vesicularity on bulk magma properties such as viscosity and density? In this contribution, we review the state of the art for models of mixing and mingling processes and how they have been informed by field, analytical, experimental and numerical investigations. We then show how analytical observations of mixed and mingled lavas from four volcanoes (Chaos Crags, Lassen Peak, Mt. Unzen and Soufrière Hills) have been used to infer a conceptual model for mixing and mingling dynamics in magma storage regions. Finally, we review recent advances in incorporating multi-phase effects in numerical modelling of mixing and mingling, and highlight the challenges associated with bringing together empirical conceptual models and theoretically-based numerical simulations.

Madhav Patel and Athanasios K. Karamalidis*Energy and Minerals Engineering, Pennsylvania State University, State College, PA 16802 USA (*correspondence: [email protected])

The Himalayan orogen exposes a range of metamorphosed assemblages, from low-grade Indian shelf sediments of the Tethyan Formation to eclogite and ultra-high pressure rocks documented near the suture zone between the Indian craton and Asian subcontinent. Barrovian-grade pelites and mafic protoliths are exposed in the Himalayan core and include the Greater Himalayan Crystallines and Lesser Himalayan Formations. These units are separated by the Main Central Thrust (MCT). This fault system accommodated a significant amount of India-Asia convergence and is the focus of several models that explore ideas about the development of the range and collisional belts in general. These units provide critical information regarding the mechanisms of heat transfer within collisional belts. Garnets collected across the MCT record their growth history through changes in chemistry. These chemical changes can be extracted and modeled using a variety of thermodynamic approaches. This paper reviews the geological framework of the Himalayas with a focus on the protolith of its metamorphosed assemblages. It describes and applies particular thermobarometric techniques to decipher the metamorphic history of several garnet-bearing rocks collected across the MCT in central Nepal. Comparisons are made between the results of previously-reported conventional rim P-T conditions and P-T paths extracted using the Gibb’s method to isopleth thermobarometry and high-resolution P-T path modeling using the same data and assemblages. Predictions of the paths on garnet zoning are also presented for the high-resolution P-T path modeling and Gibb’s method using the program TheriaG. Although the approaches yield different absolute conditions and P-T path shapes, all are consistent with the development of the MCT shear zone due to imbrication of distinct rock packages. Greater Himalayan Crystalline garnets experienced higher-grade conditions that make extracting its P-T conditions and paths a challenge. Lesser Himalayan garnets appear to behave as closed systems and are ideally suited for thermodynamic approaches.

The latest work on the main African rivers on the Atlantic coast has made it possible to subdivide the multi-year streamflow records into several homogeneous phases. The year 1970 seems to mark both for West and Central Africa the major hydroclimatic event of the 20th century, heralding its main period of deficit flow. For the first time, this article presents a comparative study of the hydro-rainfall records of five drainage systems (those of the Congo River and its main tributaries Lualaba, Kasai, Sangha, Oubangui) based on field data, obtained on both the left and right banks of the Congo River. A reconstitution of the Cuvette Centrale regime is proposed. The 1970 hydro-rainfall disruption is common in most tributaries of the Congo River basin, with significant reductions in flows depending on various factors (geographical location, vegetation cover, surface conditions and land use, etc.). The Oubangui is the most fragile northern tributary that continues to suffer from flow deficits, with an increase in the duration and intensity of its low flows. Since 1995, flows of the Congo River at its main station in Brazzaville/Kinshasa seem to have returned to the interannual average since 1903. However, from the same year onwards, an increase in seasonal variability and a decrease in spring flood flows can also be observed for its bimodal tributaries. This article explains some of the hydrological paradoxes specific to this basin, which illustrate the complexity of its hydrological functioning. Finally, it shows that the period of excess flow in the 1960s is the major hydrological anomaly of the Congo River over a continuous 116-year history. For the whole basin, hydrological variations are attenuated compared to those of precipitation. Finally, the hydrometric regimes reconstructed by spatial altimetry and modelling are compared with those from in situ data.

Changes in precipitation extremes remain a key uncertainty as the climate warms. Improved understanding of their evolution is crucial for effective water management. A number of studies have demonstrated various scaling relationships between precipitation extremes and several different environmental variables. In this chapter, we review recent important advances in two of these relationships primarily based on observations: The scaling of precipitation extremes with surface temperature (both air temperature and dew point temperature) and convective available potential energy (CAPE). Two up-to-date global daily datasets are also used to provide a further check on the generality of earlier findings. Known scaling relationships are used to quantify the impacts of these two factors on precipitation extremes. Results show that both of them play important roles, but their impacts vary over different regions on various time scales, highlighting the challenges of constructing global relationships to explain the changing nature of precipitation extremes.

Conceptual hydrological models imply a simplification of the complexity of the hydrological system; however, it lacks the flexibility in reproducing a wide range of the catchment responses. Usually, a trade-off is done to sacrifice the accuracy of a specific aspect of the system behavior in favor of the accuracy of other aspects. This study evaluates the benefit of using a modular approach, “The fuzzy committee model” of building specialized models (same structure associated with different parameter realization) to reproduce specific responses (high and low flow response) of the catchment. The study also assesses the applicability of using predicted runoff from both specialized models with certain weights based on a fuzzy membership function to form a fuzzy committee model. This research continues to explore the fuzzy committee models first presented by [Solomatine, 2006] and further developed by [Fenicia et al., 2007; Kayastha et al., 2013]. In this paper, weighting schemes with power parameter values are investigated. A thorough study is conducted on the relation between the fuzzy committee variables (the membership functions and the weighting schemes), and their effect on the model performance. Furthermore, the Fuzzy committee concept is applied on a conceptual distributed model with two cases, the first with lumped catchment parameters and the latter with distributed parameters. A comparison between different combinations of the fuzzy committee variables showed the superiority of all Fuzzy Committee models over single models. Fuzzy committee of distributed models performed well, especially in capturing the highest peak in the calibration data set; however, it needs further study of the effect of model parameterization on the model performance and uncertainty.

A variety of smoke model frameworks are used to simulate smoke for research and forecast applications. Here, a comprehensive summary is provided which covers the many different smoke models that are available, while simultaneously highlighting some of the strengths and weaknesses of each model, along with the uncertainties surrounding each of these frameworks. This review also provides an in-depth discussion on coupled wildfire-atmosphere models, which is a relatively newer smoke modeling tool not previously discussed in other review papers. Key processes related to smoke transport and dispersion, such as the wildfire plume rise, are also discussed in length. This review wraps up with a discussion of future smoke modeling needs and potential new research directions for smoke transport and dispersion models.

Plate Motion Change at ca. 6 MaJacob L. Rosenthal1, Paul G. Fitzgerald1, Jeffrey A. Benowitz2, James R. Metcalf2, Paul M. Betka31Department of Earth and Environmental Sciences, Syracuse University , Syracuse NY 13244, USA2Department of Geological Sciences, University of Colorado Boulder , Boulder Co 80309, USA3Atmospheric, Oceanic, and Earth Sciences Department , George Mason University, Fairfax VA 22030, USACorresponding author: Jacob Rosenthal ([email protected])