Pyroclastic Density Currents (PDCs) are the most dangerous hazard associated with explosive volcanic eruptions. Due to the danger associated with observing these ground-hugging currents of searing hot gas, ash, and rock in real time, their processes are poorly understood. In order to understand flow dynamics, including what controls how far PDCs travel and how they interact with topography, it is necessary to study their deposits. The May 18th, 1980 eruption of Mt. St. Helens produced multiple PDCs, burying the area north of the volcano under tens of meters of PDC deposits. The eruption is one of the best observed on record, and deep drainage erosion over the past 30 years has exposed the three-dimensional structure of the PDC deposits, making this intensive study possible. For each flow unit we measure deposit thickness, bedding style, clast size, density and sorting, and degree of pumice rounding with distance from source. The intricate vertical and lateral facies changes and complex cross-cutting relationships away from source, including rapid changes in bedding and granulometry characteristics within each unit, indicate that the currents interacted with complex topography early in their propagation. We use this observation and analysis to better understand and interpret flow dynamics. The data we collect will be used to refine and validate numerical models of PDCs, ultimately providing a more accurate hazard assessment for explosive eruptions.

Perception of natural hazards and risk among Pacific Northwest (PNW) residents is not well known. Familiarity with a given population's perception of natural hazards and the threats they present is vital for the development of effective education prior to and emergency management response after a natural event. While much work has been done in other active tectonic regions, little work has been completed in our region. The objective of this work is to assess the current perception of earthquake and volcanic hazards in the PNW, and to better understand the factors which drive the public's behavior concerning preparedness and response. We developed a survey to assess the participants' knowledge of natural hazards common to the region, perception of risk concerning these hazards, and level of preparedness should a natural hazard occur. The survey was distributed to the PNW public via a class project in 'Living with Volcanoes' (ESS 106) in March of 2011 and 2012, which returned more than 1000 responses. Here we highlight the responses from the UW student population because of their uniqueness as a large semi-transient population (typical residence of less than 5 years). Knowledge of natural hazards and proximity to hazard sources was found to be low/inaccurate, which corresponds to a low perception of risk. Understanding/awareness of evacuation/coping protocol for natural hazards was also found to be low, suggesting this large, semi-transient population lacks the understanding of proper preparation for and response to a natural hazard. Results from the survey indicate need for education of this population concerning the risks of natural hazards in this region and the steps for better preparedness. The ultimate goal of further education is to create a "culture of safety" rather than "moments of reaction" (USGS initiative).

 The effect of viral evolution on the duration of latency in Human Immunodeficiency Virus Type 1 (HIV-1) infection has been studied extensively in men. The asymptomatic latency period, after HIV-1 infection and before the onset of Acquired Immune Deficiency Syndrome (AIDS), is characterized by high viral variability. In many cases, a viral phenotype that utilizes CXCR4 and/or CCR5 receptors on target host cells to advance HIV-1 infection progress also emerges during this period. Despite known sex-dependent variation in the progression of HIV-1, the effect of viral evolution and CXCR4/CCR5 utilizing virus (X4 virus) prevalence on HIV-1 latency has not yet been studied in women. I am investigating trends in viral evolution in 9 women from seroconversion until initiation of antiretroviral therapy. I will then compare my results to previously studied male viral evolutionary trends. Ultimately, a total of 72 blood plasma samples, an average of 8 samples from each woman collected progressively during the course of infection, will be used to generate 25-30 HIV-1 sequences per time point. These sequences will then be evaluated through 1) viral divergence from a founder strain 2) viral population diversity and 3) emergence and prevalence of X4 viruses. I will then analyze the relationship between viral evolutionary trends and X4 virus prevalence, and the duration of HIV-1 infection before the onset of AIDS. Ultimately, a comparison between the sexes will be made. Furthering the scientific communities’ knowledge of sex-related HIV-1 infection variation could lead to more effective sex-specific treatment and vaccine development. The important biological question of whether sex can influence HIV-1’s evolutionary path will be addressed. This project is currently in the preliminary stage of sequence generation. Trend analysis and conclusions will take place in Fall 2012.