Physical Sciences and Mathematics Commons^™

Dynamic Relationship Study Between The Observed Seismicity And Spatiotemporal Pattern Of Lineament Changes In Palghar, North Maharashtra (India), Biswajit Nath, Ramesh P. Singh, Vineet K. Gahalaut, Ajay P. Singh

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The Palghar region (north Maharashtra, India), located in the northwestern part of the stable continental region of India, experienced a low magnitude earthquake swarm, which was initiated in September 2018 and is continuing to date (as of October 2021). From December 2018 to December 2020, ~5000 earthquakes with magnitudes from M1.2 to M3.8 occurred in a small region of 20 × 10 km². These earthquakes were probably triggered by fluid migration during seasonal rainfall. In this study, we have used multi-temporal Landsat satellite data of the year 2000, 2015, 2018, 2019, and 2020, extracted lineaments, and studied the …

A Mathematical Model For Transport And Growth Of Microbes In Unsaturated Porous Soil, Harihar Khanal, Andrei Ludu, Ramesh Chandra Timsina, Kedar Nath Uprety

Publications

In this work, we develop a mathematical model for transport and growth of microbes by natural (rain) water infiltration and flow through unsaturated porous soil along the vertical direction under gravity and capillarity by coupling a system of advection diffusion equations (for concentration of microbes and their growth-limiting substrate) with the Richards equation. (e model takes into consideration several major physical, chemical, and biological mechanisms. (e resulting coupled system of PDEs together with their boundary conditions is highly nonlinear and complicated to solve analytically. We present both a partial analytic approach towards solving the nonlinear system and finding the main …

Progressive Destabilization And Triggering Mechanism Analysis Using Multiple Data For Chamoli Rockslide Of 7 February 2021, Wenfei Mao, Lixin Wu, Ramesh P. Singh, Yuan Qi, Busheng Xie, Yingjia Liu, Yifan Ding, Zilong Zhou, Jia Li

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

A catastrophic rockslide occurred on 7 February 2021 in Chamoli area in the high Himalaya. In the absence of field data, multiple satellites data of decade span have been used to investigate and understand the progressive destabilization of rockslide body. A 3D geometric model was developed using geospatial information about geology, terrain, and ice cover to understand the triggering mechanism. Several causes are uncovered as: the pronounced long-term change of land surface temperature facilitated local permafrost degradation and led to ice cover shrinking since 2010; the occurrence of ice avalanche nearby in 2016 accompanying with sidewall-to-bedrock fracturing enhanced the ice …

Linking Migration To Community Resilience In The Receiving Basin Of A Large-Scale Water Transfer Project, Anna Erwin, Zhao Ma, Ruxandra Popovici, Emma Patricia Salas O’Brien, Laura Zanotti, Chelsea A. Silva, Eliseo Zeballos Zeballos, Jonathan Bauchet, Nelly Ramírez Calderón, Glenn Roberto Arce Larreah

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Large-scale water transfer projects (LWTPs) transfer water to urban and agricultural areas. The Majes-Siguas canal, established in 1983, is an LWTP that created a thriving agricultural area through irrigating the Majes district in the Atacama Desert of Peru. Like other LWTP receiving basins, the project has attracted an influx of migrants who work on the farms. At the same time, the Majes LWTP is the district’s only source of water and has an aging infrastructure which presents significant risks. While many studies critically analyze the consequences of LWTPs in water supply basins, few evaluate the resilience of communities living in …

2021 Grand River Water Quality, Allison Romanski, Madeleine Lang

Student Summer Scholars Manuscripts

2021 Grand River Water Quality Sampling

The goals of this research project were to collect repeat samples at designated reaches and under different flow conditions along the Grand River, sample the entire Grand River over a short period of time, collaborate with wastewater treatment plant labs and technicians to analyze water samples, and to calculate a Water Quality Index (WQI) for samples collected.

Seven different reaches were sampled and over 120 samples were collected between May 7th and August 12th of 2021. Water samples were collected and analyzed for nitrate, total phosphate, ammonium, chloride, dissolved oxygen, biological oxygen demand , …

Cuny York College–Hosted Nasa Stem Outreach Program Graduates Over 30,000 Students – The Legacy Continues Amidst The Covid-19 Pandemic, Nazrul I. Khandaker

Publications and Research

The NASA MUREP (Minority University Research and Education Project) and SEMAA (Science, Engineering, Mathematics and Aerospace Academy) at York College CUNY (City University of New York), borough of Queens, New York City, recently earned a distinction by graduating over 30,000 underrepresented minority students since 1999 with the culmination of the fall 2021 session! African American students are leading the graduates, followed by Hispanic and Asian students being almost equal in proportion. The primary objective of both MAA (MUREP Aerospace Academy) and SEMAA is getting underrepresented minority students exposure to innovative STEM content and prepare many of them to enter higher …

Primary Versus Secondary Gravity Wave Responses At F-Region Heights Generated By A Convective Source, C. J. Heale, P. A. Inchin, J. B. Snively

Publications

A 2D nonlinear, compressible model is used to simulate the acoustic-gravity wave (AGW, i.e., encompassing the spectrum of acoustic and gravity waves) response to a thunderstorm squall-line type source. We investigate the primary and secondary neutral AGW response in the thermosphere, consistent with waves that can couple to the F-region ionospheric plasma, and manifest as Traveling Ionospheric Disturbances (TIDs). We find that primary waves at z = 240 km altitude have wavelengths and phase speeds in the range 170–270 km, and 180–320 m/s, respectively. The secondary waves generated have wavelengths ranging from ∼100 to 600 km, and phase speeds from …

Stimulation Of Ammonia Oxidizer And Denitrifier Abundances By Nitrogen Loading: Poor Predictability For Increased Soil N2o Emission, Yong Zhang, Feng Zhang, Diego Abalos, Yiqi Luo, Dafeng Hui, Bruce A. Hungate, Pablo García-Palacios, Yakov Kuzyakov, Jørgen Eivind Olesen, Uffe Jørgensen, Ji Chen

Biology Faculty Research

Unprecedented nitrogen (N) inputs into terrestrial ecosystems have profoundly altered soil N cycling. Ammonia oxidizers and denitrifiers are the main producers of nitrous oxide (N₂O), but it remains unclear how ammonia oxidizer and denitrifier abundances will respond to N loading and whether their responses can predict N-induced changes in soil N₂O emission. By synthesizing 101 field studies worldwide, we showed that N loading significantly increased ammonia oxidizer abundance by 107% and denitrifier abundance by 45%. The increases in both ammonia oxidizer and denitrifier abundances were primarily explained by N loading form, and more specifically, organic N …

Numerical Modeling Of Mineralizing Processes During The Formation Of The Yangzhuang Kiruna-Type Iron Deposit, Middle And Lower Yangtze River Metallogenic Belt, China: Implications For The Genesis And Longevity Of Kiruna-Type Iron Oxide-Apatite Systems, Xunyu Hu, Simon Jowitt, Feng Yuan, Guangxian Liu, Jinhui Luo, Yuhua Chen, Hui Yang, Keyue Ren, Yongguo Yang

Geoscience Faculty Research

The Yangzhuang iron deposit is a Kiruna-type iron oxide-apatite (IOA) deposit within the Ningwu mining district of the Middle and Lower Yangtze River Metallogenic Belt (MLYRMB), China. This study applies a numerical modeling approach to identify the key processes associated with the formation of the deposit that cannot be easily identified using traditional analytical approaches, including the duration of the mineralizing process and the genesis of iron orebodies within intrusions associated with the deposit. This approach highlights the practical value of numerical modeling in quantitatively analyzing mineralizing processes during the formation of mineral deposits and assesses how these methods can …

Source Apportionment And Health Risk Assessment Of Nitrate In Foothill Aquifers Of Western Ghats, South India, Banajarani Panda, S. Chidambaram, Daniel D. Snow, Arindam Malakar, Dhiraj Kr Singh, L. Ramanathan

Nebraska Water Center: Faculty Publications

The present research reports the level of nitrate (NO₃^-), associated health risks and possible sources of contamination in groundwater from south India. Many samples (32%) are above or approaching the recommended level of NO₃^- for safe drinking water. The correlation analysis indicates different sources of NO₃^- contamination in different regions rather than a common origin. The isotopic measurements provide information about potential nitrogen sources contributing NO₃^- to the groundwater. Based on isotope analysis, the sources of NO₃^- in the groundwater of this region are likely to be from (a) …

Late Cretaceous Paleoceanographic Evolution And The Onset Of Cooling In The Santonian At Southern High Latitudes (Iodp Site U1513, Se Indian Ocean), Maria Rose Petrizzo, Kenneth G. Macleod, David K. Watkins, Erik Wolfgring, Brian T. Huber

Department of Earth and Atmospheric Sciences: Faculty Publications

The latest Cenomanian to Santonian sedimentary record recovered at IODP Expedition 369 Site U1513 in the Mentelle Basin (SE Indian Ocean, paleolatitude 60°S at 85 Ma) is studied to interpret the paleoceanographic evolution in the Southern Hemisphere. The planktonic foraminiferal assemblage changes, the depth ecology preferences of different species, and the surface and seafloor temperature inferred from the stable isotopic values measured on foraminiferal tests provide meaningful information to the understanding of the Late Cretaceous climate. The hothouse climate during the Turonian-Santonian, characterized by weak latitudinal temperature gradients and high atmospheric CO₂ concentrations, is followed by a progressive cooling …

Quantification Of Mineral Reactivity Using Machine Learning Interpretation Of Micro-Xrf Data, Julie J. Kim, Florence Ling, Dan A. Plattenberger, Andres F. Clarens, Catherine A. Peters

Environmental Science Faculty Work

Accurate characterizations of mineral reactivity require mapping of spatial heterogeneity, and quantifications of mineral abundances, elemental content, and mineral accessibility. Reactive transport models require such information at the grain-scale to accurately simulate coupled processes of mineral reactions, aqueous solution speciation, and mass transport. In this work, millimeter-scale mineral maps are generated using a neural network approach for 2D mineral mapping based on synchrotron micro x-ray fluorescence (μXRF) data. The approach is called Synchrotron-based Machine learning Approach for RasTer (SMART) mapping, which reads μXRF scans and provides mineral maps of the same size and resolution. The SMART mineral classifier is trained …

Fungal Community And Functional Responses To Soil Warming Are Greater Than For Soil Nitrogen Enrichment, Mark A. Anthony, Melissa A. Knorr, Jessica A. M. Moore, M. Simpson, Serita D. Frey

Faculty Publications

Soil fungi are key regulators of forest carbon cycling and their responses to global change have effects that ripple throughout ecosystems. Global changes are expected to push many fungi beyond their environmental niches, but there are relatively few studies involving multiple, simultaneous global change factors. Here, we studied soil fungal diversity, community composition, co-occurrence patterns, and decomposition gene responses to 10 years of soil warming and nitrogen addition, alone and in combination. We specifically examined whether there were fungal community characteristics that could explain changes in soil carbon storage and organic matter chemistry in chronically warmed and fertilized soil. We …

Changing Impacts Of Alaska-Aleutian Subduction Zone Tsunamis In California Under Future Sea-Level Rise, Tina Dura, Andra J. Garner, Robert Weiss, Robert E. Kopp, Simon E. Engelhart, Robert C. Witter, Richard W. Briggs, Charles S. Mueller, Alan R. Nelson, Benjamin P. Horton

School of Earth & Environment Faculty Scholarship

The amplification of coastal hazards such as distant-source tsunamis under future relative sea-level rise (RSLR) is poorly constrained. In southern California, the Alaska-Aleutian subduction zone has been identified as an earthquake source region of particular concern for a worst-case scenario distant-source tsunami. Here, we explore how RSLR over the next century will influence future maximum nearshore tsunami heights (MNTH) at the Ports of Los Angeles and Long Beach. Earthquake and tsunami modeling combined with local probabilistic RSLR projections show the increased potential for more frequent, relatively low magnitude earthquakes to produce distant-source tsunamis that exceed historically observed MNTH. By 2100, …

Comprehensive Report On Extraterrestrial Resource Extraction, Robinson Raphael

Student Works

The prospect of asteroid mining provides a plethora of riches that include metals and water. As the number of discovered asteroids continues to grow, opportunities arise to commercialize these resources within Near-Earth Asteroids (NEAs). With urgent applications on Earth and in space, NEAs allow for a surge in sales. Planning forward, Astroider Aerospace Systems follows a mission split into four phases. Phase 1 develops a series of spacecraft using existing technologies, titled as Near-Earth Asteroid Miners and Near-Earth Asteroid Surveyors. Phase 2 first launches the surveyors to candidate NEAs, prospecting them for ores. To identify potential celestial bodies for this …

Implications From Uranium-Series Disequilibria In A Bi-Lithologic Melt With Varying Lithospheric Caps, Juliet Messer

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Both spreading rates and local magma supply to mid-ocean ridges affect crustal construction styles and ridge morphology, alternately leading to either asymmetrical (detachment faulting) or symmetrical faulting styles. Uranium-series isotopic disequilibria in mid-ocean ridge basalts (MORB) may provide insight into how melt supply variations relate to ridges’ accretion styles, a processes that are not well understood. I use Reactive Porous Flow (RPF) equilibrium and disequilibrium modeling to simulate U-series disequilibria at mid-ocean ridge (MOR) generated by melt supply variations at both asymmetrical and symmetrical ridge segments.

Guided by my modeling, I predict that enhanced melt contributions from enriched pyroxenitic mantle …

Biostratigraphy Of Paleogene Diatom Assemblages In The Southern Ocean, Angela Kaup

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The record of siliceous microfossil sedimentation in the high latitude South Atlantic Ocean has great potential for dating seismic and stratigraphic units. Over the last several decades, scientists have documented diatom biostratigraphic record from sediment cores and drill cores in the Falkland Plateau and Maurice Ewing Bank region, as well as other areas of the Southern Ocean, and a robust chronostratigraphic framework is available for Neogene sequences. Given the complicated nature of ocean bathymetry, tectonic plate motion (vertical and lateral), and ocean current flow, the sedimentological evolution of this oceanic region is not well understood. Sampling sediment cores at high …

Soil Microbial Community Dynamics In Response To Prescribed Extreme Fires Following Juniperus Virginiana Invasion In The Loess Canyons Of Nebraska, Julie A. Fowler

School of Natural Resources: Dissertations, Theses, and Student Research

In Nebraska and other regions of the Great Plains, the conifer Juniperus virginiana (eastern redcedar) is converting grasslands to dense woodlands. This is driven by the interacting drivers of fire suppression, altered grazing regimes, climate change and other anthropogenic factors, impacting the provisioning of ecosystem services. This vegetation state transition modifies water resource regulation and biogeochemical cycles leading to altered edaphic properties including soil microbial community composition. To restore these grasslands and control J. virginiana spread, prescribed extreme burns are implemented as a management tool through local prescribed burn associations. We hypothesized that the alternative state transition to dense J. …

Rhizobium Symbiotic Capacity Shapes Root-Associated Microbiomes In Soybean, Yuanhui Lu, Bin Ma, Wenfeng Chen, Klaus Schlaeppi, Matthias Erb, Erinne Stirling, Lingfei Hu, Entao Wang, Yunzeng Zhang, Kankan Zhao, Zhijiang Lu, Shudi Ye, Jianming Xu

Environmental Science and Geology Faculty Research Publications

Root-microbiome interactions are of central importance for plant performance and yield. A distinctive feature of legumes is that they engage in symbiosis with N₂-fixing rhizobia. If and how the rhizobial symbiotic capacity modulates root-associated microbiomes are still not yet well understood. We determined root-associated microbiomes of soybean inoculated with wild type (WT) or a noeI mutant of Bradyrhizobium diazoefficiens USDA 110 by amplicon sequencing. UPLC-MS/MS was used to analyze root exudates. The noeI gene is responsible for fucose-methylation of Nod factor secreted by USDA 110 WT strain. Soybean roots inoculated with the noeI mutant showed a significant decrease …

Proliferation Of Chondrodonta As A Proxy Of Environmental Instability At The Onset Of Oae1a: Insights From Shallow-Water Limestones Of The Apulia Carbonate Platform, G. Del Viscio, G. Frijia, R. Posenato, P. Singh, Daniel J. Lehrmann, J. L. Payne, K. Al-Ramadan, U. Struck, K. P. Jochum, M. Morsilli

Geosciences Faculty Research

Chondrodonta is an opportunistic, oyster-like bivalve, common in shallow-water carbonates of the Cretaceous Tethyan Realm. Despite its high abundance and widespread geographic distribution, the precise relationship between the early Aptian proliferation and environmental perturbations resulting from the Oceanic Anoxic Event 1a (OAE1a), has not been investigated. Stratigraphic and geochemical analyses of the lower Aptian Chondrodonta bedsets within the inner platform limestones of the Apulia Carbonate Platform (Gargano Promontory, southern Italy) are conducted to assess the environmental controls on the Chondrodonta proliferation and its timing and causal relationship to OAE1a. Chondrodonta occurs with sparse to common individuals within requieniid rudist floatstone–rudstones, …

Fingerprinting The Cretaceous-Paleogene Boundary Impact With Zn Isotopes, Ryan Mathur, Brandon Mahan, Marissa Spencer, Linda Godfrey, Neil Landman, Matthew Garb, D. Graham Pearson, Sheng-Ao Liu, Francisca Oboh-Ikuenobe

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Numerous geochemical anomalies exist at the K-Pg boundary that indicate the addition of extraterrestrial materials; however, none fingerprint volatilization, a key process that occurs during large bolide impacts. Stable Zn isotopes are an exceptional indicator of volatility-related processes, where partial vaporization of Zn leaves the residuum enriched in its heavy isotopes. Here, we present Zn isotope data for sedimentary rock layers of the K-Pg boundary, which display heavier Zn isotope compositions and lower Zn concentrations relative to surrounding sedimentary rocks, the carbonate platform at the impact site, and most carbonaceous chondrites. Neither volcanic events nor secondary alteration during weathering and …

Sedimentary Dna And Molecular Evidence For Early Human Occupation Of The Faroe Islands, Lorelei Curtin, William J. D’Andrea, Nicholas L. Balascio, Sabrina Shirazi, Beth Shapiro, Gregory A. De Wet, Raymond S. Bradley, Jostein Bakke

Geosciences: Faculty Publications

The Faroe Islands, a North Atlantic archipelago between Norway and Iceland, were settled by Viking explorers in the mid-9th century CE. However, several indirect lines of evidence suggest earlier occupation of the Faroes by people from the British Isles. Here, we present sedimentary ancient DNA and molecular fecal biomarker evidence from a lake sediment core proximal to a prominent archaeological site in the Faroe Islands to establish the earliest date for the arrival of people in the watershed. Our results reveal an increase in fecal biomarker concentrations and the first appearance of sheep DNA at 500 CE (95% confidence interval …

Measuring Ecosystem Services From Soil Health. Vermont Payment For Ecosystem Services Technical Research Report #1, Alissa C. White, Heather M. Darby, Benjamin Timothy Dube, Bryony Sands, Joshua W. Faulkner, Meredith Albers, Maggie Payne

UVM Extension Faculty Publications

There are a multitude of approaches to evaluating soil health and the soil processes influenced by soil health. As the state of Vermont explores innovative programs that compensate farmers for soil health and associated ecosystem services, the selection of soil health indicators and quantification methods is a foundational first step that influences other aspects of program design. What is measured determines the ecosystem services that can be inferred, the accuracy of data that informs decisions, and programmatic transaction costs. Simply put, what is measured matters. The PES Working Group identified organic matter, bulk density, aggregate stability, greenhouse gas flux from …

American Burying Beetle, Plant Richness, And Soil Property Responses To Collapse Of Juniperus Virginiana Woodlands With Fire, Alison Ludwig

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Grasslands are declining in the Great Plains due to land use changes, woody plant encroachment, and loss of historic fire cycles. Prescribed burn associations have utilized prescribed fire to collapse invading woodlands and allow the restoration of grasslands. This fire is considered “extreme” because it is capable of changing the structure and function of an ecosystem. Our study site is the Loess Canyons Experimental Landscape, a long-term, ecoregion-scale experiment to apply prescribed fire across the region to restore grasslands. The Nebraska Natural Legacy Project established the Loess Canyons ecoregion as a Biologically-Unique Landscape in 2005 with the state’s wildlife action …

Unusual Intraclast Conglomerates In A Stormy, Hot-House Lake: The Early Triassic North China Basin, Kaixuan Ji, Paul B. Wignall, Jeff Peakall, Jinnan Tong, Daoliang Chu, Sara B. Pruss

Geosciences: Faculty Publications

Early Triassic temperatures were some of the hottest of the Phanerozoic, sea-surface temperatures approached 40°C, with profound consequences for both the sedimentology and faunal distributions in the oceans. However, the impact of these temperatures in terrestrial settings is unclear. This study examines shallow lacustrine sediments from the Lower Triassic succession of North China. These consist of diverse fluvial to shallow lacustrine sandstones and also spectacular, coarse conglomerates composed of diverse, intraformational clasts reworked from the interbedded sediments. The conglomerate beds can show inverse grading and high angle, flat-pebble imbrication in their lower part and vertically orientated flat pebbles in their …

Investigating Strike-Slip Faulting Parallel To The Icelandic Plate Boundary Using Boundary Element Models, Anna E.R. Pearson, John P. Loveless

Geosciences: Faculty Publications

Most faults in Iceland strike roughly parallel to the divergent plate boundary, a part of the North American-Eurasian plate boundary, which would be expected to lead to primarily normal faulting. However, several studies have observed a significant component of rift-parallel strike-slip faulting in Iceland. To investigate these fault kinematics, we use the boundary element method to model fault slip and crustal stress patterns of the Icelandic tectonic system, including a spherical hotspot and uniaxial stress that represents rifting. On a network of faults, we estimate the slip required to relieve traction imposed by hotspot inflation and remote rifting stress and …

Assessment Of Soil Sampling Equipment For Guiding Fertiliser Decisions, David Weaver, Robert Summers, David Rogers, Peta Richards, David Rowe

Resource management technical reports

A range of methods, technologies and equipment are used to collect representative composite soil samples from paddocks. Once collected, soil samples are analysed for various parameters that provide evidence to guide fertiliser decisions. The sampling methods, technologies and equipment used must result in samples that consistently represent the parameter of interest.

Soil sampling technology and equipment has advanced from manual devices (such as pogo-stick-style foot-thrust core samplers [pogo]) to a variety of mechanised core-thrust samplers and augers that are fitted to vehicles or battery drills. Each device may function differently under different conditions, and each requires differing levels of human …

Soil Structure And Soil Moisture Dynamics Inferred From Time-Lapse Electrical Resistivity Tomography, Travis Nielson, John Bradford, Jen Pierce, Mark Seyfried

Geosciences Faculty Publications and Presentations

The semi-arid sagebrush steppe in the western United States faces pressures from the agriculture industry, recreation use, invasive grasses, and a changing climate. A key to facilitating the healthy management of this ecosystem is understanding the distribution and behavior of soil moisture in the vadose zone in both natural and agricultural settings. Within unsaturated environments, soil moisture is spatially and temporally heterogeneous, and changes in porosity and permeability within arid soils complicate characterization of soil hydrologic properties. Importantly, accumulations of ‘caliche’ or pedogenic calcium carbonate in arid soils can greatly limit permeability; however, observing the role that caliche plays in …

Understanding The Multiple Small Magnitude Induced Seismic Soil Fatigue Potential On Hazard Assessments, Merissa L. Zuzulock, Oliver Denzil S. Taylor, Norbert H. Maerz

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Soils under spacio-temporally clustered events loading are susceptible to soil fatigue as pore pressure dissipates and the soil is unable to recover. This potential for damage from soil fatigue is identified through an induced seismic fatigue equation provided in this paper. The objective of this paper is to present an induced seimic equation for soils under spacio-temporally clustered impulse loading to identify potential hazards to the subsurface that supports critical infrastructure. It further illustrates the use of the equation as determined from a comparison of three varying soil profiles with resulting data that shows a need to establish new critieria …

Relationship Between Dike Injection And B-Value For Volcanic Earthquake Swarms, Allen F. Glazner, Stephen R. Mcnutt

School of Geosciences Faculty and Staff Publications

Dike swarms are the fossil remains of regions of the crust that have undergone repeated magma injections. Volcanic earthquake swarms and geodetic measurements are, at least in part, a record of active injection of fluids (water, gas, or magma) into fractures. Here, we link these two ways of observing magmatic systems by noting that dike thicknesses and earthquake magnitudes share similar scaling parameters. In the Jurassic Independence dike swarm of eastern California median dike thickness is ∼1 m, similar to other swarms worldwide, but glacially polished exposures reveal that a typical dike comprises a number of dikelets that are lognormally …