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  • Results from simulations of earthquake rupture in fault zones with along-strike heterogeneity

    Work
    Creator: Huang, Yihe
    Description: Geological and geophysical observations reveal along-strike fault zone heterogeneity on major strike-slip faults, which can play a significant role in earthquake rupture propagation and termination. I present 2D dynamic rupture simulations to demonstrate rupture characteristics in such heterogeneous fault zone structure. The modeled rupture is nucleated in a damaged fault zone and propagates on a preexisting fault towards the zone of intact rocks. There is an intermediate range of nucleation lengths that only allow rupture to spontaneously propagate in the damaged fault zone but not in a homogeneous medium. I find that rupture with an intermediate nucleation length tends to stop when it reaches the zone of intact rocks, especially when the rupture propagation distance in the damaged fault zone is relatively short and when the damaged fault zone is relatively narrow or smooth in the fault-normal direction. Pronounced small-scale heterogeneity within the damaged fault zone also contributes to such early rupture termination. In asymmetric fault zones bisected by a bimaterial fault, rupture moving in the direction of slip of faster rocks tends to terminate under the same conditions as in symmetric fault zones, whereas rupture moving in the direction of slip of slower rocks can penetrate into the zone of intact rocks. Break-through rupture is allowed when a sufficiently-large asperity is located at the edge of the zone of intact rocks. The results suggest the along-strike fault zone heterogeneity can play a critical role in seismicity distribution. The data set contains multiple folders of simulation results from the SEM2DPACK that demonstrate the above findings. The folder name includes the model parameters in each simulation as explained in the README file. The Flt01_sem2d.data file in the folder documents the slip, slip rate and stresses from each simulation. The files are also explained in the manual of SEM2DPACK (http://web.gps.caltech.edu/~ampuero/soft/users_guide_sem2dpack.pdf). Please refer to section 4.6 in the manual and use “sem2d_read_fault.m” in the POST folder of SEM2DPACK to plot the results.
  • Anthropogenic Aerosol indirect effects in cirrus clouds

    Work
    Creator: Penner, Joyce E., Zhou, Cheng, Garnier, Anne, and Mitchell, David
    Description: This data set contains the scripts and data sets needed to create the 9 figures in the referenced publication.
  • Downloaded IAAF Sprint Results in all Heats for 2004 - 2016 Olympics for both Men and Women

    Work
    Creator: Mirshams Shahshahani, Payam
    Description: Investigating minimum human reaction times is often confounded by the motivation, training, and state of arousal of the subjects. We used the reaction times of athletes competing in the shorter sprint events in the Athletics competitions in recent Olympics (2004-2016) to determine minimum human reaction times because there's little question as to their motivation, training, or state of arousal. The reaction times of sprinters however are only available on the IAAF web page for each individual heat, in each event, at each Olympic. Therefore we compiled all these data into two separate excel sheets which can be used for further analyses.
  • Multi-Stage Attack Graph Security Games: Heuristic Strategies, with Empirical Game-Theoretic Analysis --- Dataset

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    Creator: Nguyen, Thanh H., Wright, Mason, Wellman, Michael P., and Singh, Satinder
    Description: In this work , we study the problem of allocating limited security countermeasures to protect network data from cyber-attacks, for scenarios modeled by Bayesian attack graphs. We consider multi-stage interactions between a network administrator and cybercriminals, formulated as a security game. We propose parameterized heuristic strategies for the attacker and defender and provide detailed analysis of their time complexity. Our heuristics exploit the topological structure of attack graphs and employ sampling methods to overcome the computational complexity in predicting opponent actions. Due to the complexity of the game, we employ a simulation-based approach and perform empirical game analysis over an enumerated set of heuristic strategies. Finally, we conduct experiments in various game settings to evaluate the performance of our heuristics in defending networks, in a manner that is robust to uncertainty about the security environment.
  • Data from "Genomic evidence of a widespread southern distribution during the Last Glacial Maximum for two eastern North American hickory species"

    Work
    Creator: Bemmels, Jordan B. and Dick, Christopher W.
    Description: Raw SNP genotypes are provided in STRUCTURE format, with a maximum of one SNP reported per ddRAD locus. The files "caryco_SNP.str" and "caryov_SNP.str" are genotypes for Carya cordiformis and Carya ovata, respectively. The first column of each file is the individual name, the second column is the population (see original publication for information on population locations), and the remaining columns are genotypes of individual SNPs. Rows represent individuals, with the diploid genotypes contained on two lines per individual. Missing data are entered as "0" (zero). The first row is a header with a unique identifier for each SNP. and Occurrence records for each species are provided in the file "occs_carya.csv" and contain the latitude and longitude of each record.
  • Maximum Spreading Speed for Magnetopause Reconnection: Model Dataset

    Work
    Creator: Welling, Daniel and Walsh, Brian
    Description: The goal of this simulation was to examine the spread of magnetic reconnection across the dayside magnetopause upon the arrival of a tangential discontinuity of the interplanetary magnetic field from a purely northward to southward configuration. Simple solar wind conditions were used to give us input into the system. A very high resolution grid setup was used in BATS-R-US.
  • Data in support of the study "Modeled Response of Greenland Snowmelt to the Presence of Biomass Burning-Based Absorbing Aerosols in the Atmosphere and Snow"

    Work
    Creator: Ward, Jamie L., Flanner, Mark G., Bergin, Mike, Dibb, Jack E., Polashenski, Chris M., Soja, Amber J., Thomas, Jennie L.
    Description: Biomass burning produces smoke aerosols that are emitted into the atmosphere. Some smoke constituents, notably black carbon (BC), are highly effective light-absorbing aerosols (LAA). Emitted LAA can be transported to high albedo regions like the Greenland Ice Sheet (GrIS) and affect local snowmelt. In the summer, the effects of LAA in Greenland are uncertain. To explore how LAA affect GrIS snowmelt and surface energy flux in the summer, we conduct idealized global climate model simulations with perturbed aerosol amounts and properties in the GrIS snow and overlying atmosphere. The in-snow and atmospheric aerosol burdens we select range from background values measured on the GrIS to unrealistically high values. This helps us explore the linearity of snowmelt response and to achieve high signal-to-noise ratios. With LAA operating only in the atmosphere, we find no significant change in snowmelt due to the competing effects of surface dimming and tropospheric warming. Regardless of atmospheric LAA presence, in-snow BC-equivalent mixing ratios greater than ~60 ng/g produce statistically significant snowmelt increases over much of the GrIS. We find that net surface energy flux changes correspond well to snowmelt changes for all cases. The dominant component of surface energy flux change is solar energy flux, but sensible and longwave energy fluxes respond to temperature changes. Atmospheric LAA dampen the magnitude of solar radiation absorbed by in-snow LAA when both varieties are simulated. In general, the significant melt and surface energy flux changes we simulate occur with LAA quantities that have never been recorded in Greenland.
  • Supporting data and scripts for the paper "Variability in the location of High Frequency Oscillations during prolonged intracranial EEG recordings"

    Work
    Creator: Gliske, Stephen V and Stacey, William C
    Description: This data is part of a large program to translate detection and interpretation of HFOs into clinical use. A zip file is included which contains hfo detections, metadata, and Matlab scripts. The matlab scripts analyze this input data and produce figures as in the referenced paper (note: the blind source separation method is stochastic, and so the figures may not be exactly the same). A file "README.txt" provides more detail about each individual file within the zip file.
  • Model outputs for "Multi-species and multi-fluid MHD approaches for the study of ionospheric escape at Mars"

    Work
    Creator: Regoli, Leonardo H.
    Description: The data corresponds to outputs from the Mars Global Ionosphere Thermosphere Model (M-GITM), the multi-species magnetohydrodynamics (MS-MHD) and multi-fluid magnetohydrodynamics (MF-MHD) codes used during the study presented in "Multi-species and multi-fluid MHD approaches for the study of ionospheric escape at Mars" by Regoli et al.
  • Effective Fetch and Relative Exposure Index Maps for the Laurentian Great Lakes

    Work
    Creator: Mason, Lacey A., Riseng, Catherine M., Layman, Andrew J., and Jensen, Robert
    Description: Wind exposure is a key physical driver of coastal systems in aquatic environments influencing circulation and wave dynamics. A measure of wind exposure is fetch, the distance over which wind can travel across open water. In large lake systems, such as the Laurentian Great Lakes, estimating fetch has proved to be difficult due to their vast size and complex topobathymetry. Here we describe the development of two spatially discrete indicators of exposure to provide a more accurate indicator of influence of wind exposure in the nearshore of the Laurentian Great Lakes. We summarized wind data from offshore buoys and leveraged existing tools to calculate effective fetch and relative exposure index (effective fetch scaled by mean wind speed) at a 30 m grid cell resolution. We validated these models by comparing our exposure maps to the U.S. Army Corps of Engineers Wave Information Studies models and found general agreement. These exposure maps are available for public download for the years 2004-2014.