Our understanding of the frequency of large earthquakes at timescales longer than instrumental and historical records is based mostly on paleoseismic studies of fast-moving plate-boundary faults. Similar study of intraplate faults has been limited until now, because intraplate earthquake recurrence intervals are generally long (10s to 100s of thousands of years) relative to conventional paleoseismic records determined by trenching. Long-term variations in the earthquake recurrence intervals of intraplate faults therefore are poorly understood. Longer paleoseismic records for intraplate faults are required both to better quantify their earthquake recurrence intervals and to test competing models of earthquake frequency (e.g., time-dependent, time-independent, and clustered). We present the results of U-Th dating of calcite veins in the Loma Blanca normal fault zone, Rio Grande rift, New Mexico, United States, that constrain earthquake recurrence intervals over much of the past ∼550 ka-the longest direct record of seismic frequency documented for any fault to date. The 13 distinct seismic events delineated by this effort demonstrate that for >400 ka, the Loma Blanca fault produced periodic large earthquakes, consistent with a time-dependent model of earthquake recurrence. However, this time-dependent series was interrupted by a cluster of earthquakes at ∼430 ka. The carbon isotope composition of calcite formed during this seismic cluster records rapid degassing of CO 2 , suggesting an interval of anomalous fluid source. In concert with U-Th dates recording decreased recurrence intervals, we infer seismicity during this interval records faultvalve behavior. These data provide insight into the long-term seismic behavior of the Loma Blanca fault and, by inference, other intraplate faults.earthquake | fault | geochronology | seismic | hazard R ecent increases in the rate of seismicity associated with subsurface wastewater injection have generated substantial interest in the seismic cycles of intraplate faults (1-4). Unfortunately, increasing seismicity in the continental interior has outpaced our understanding of the processes that govern natural earthquake recurrence on these faults. The seismic cycles of plate boundary faults are much better known, although the exact nature of their earthquake recurrence distributions remains much debated (5, 6). At the heart of this debate lies a fundamental question: Are seismogenic faults ever controlled by a stress-renewal process that can be approximated by elastic rebound theory? The latter states that stress buildup will be accommodated elastically until shear stress on the fault reaches a threshold value that will allow failure.If seismogenic faults are governed by a renewal process, then elastic rebound theory predicts that earthquakes will be produced quasiperiodically (7) (i.e., occur at regular intervals and therefore be "time-dependent") with steady tectonic loading. However, an alternative view posits that spatial and temporal variations in fault strength and/or mechan...

Somatic mutations and genomic alterations are frequent events in the clonal evolution of hematologic malignancies. Recent studies have reported copy neutral loss of heterozygosity (LOH) for the mismatched human leukocyte antigen (HLA) haplotype in patients relapsed after haploidentical hematopoietic cell transplantation (HCT) for a hematologic malignancy. Herein, we report 15 cases of somatic mutations in the HLA genes of patients with a variety of hematologic diseases, including acute myelogenous leukemia, acute lymphocytic leukemia, chronic lymphocytic leukemia, chronic myeloid leukemia, myelodysplastic syndrome, and non-Hodgkin's lymphoma, encountered at our institute over the past decade. While two of the cases were identified in patient relapse specimens collected post-HCT, 13 cases were found in peripheral blood specimens submitted for HLA typing prior to transplantation. Ten patients exhibited acquired LOH for all or part of one HLA haplotype. Five other cases involved somatic mutations in the nucleotide sequences of common HLA-A or HLA-B alleles. Since they are not systematically evaluated prior to HCT, acquired mutations in HLA genes are likely under reported. Beyond the implications for accurate HLA typing and donor selection, alternations that result in the loss of HLA expression may allow escape from immune surveillance and adversely impact transplant outcome.

StraboSpot is a geologic data system that allows researchers to digitally collect, store, and share both field and laboratory data. StraboSpot is based on how geologists actually work to collect field data; although initially developed for the structural geology research community, the approach is easily extensible to other disciplines. The data system uses two main concepts to organize data: spots and tags. A spot is any observation that characterizes a specific area, a concept applicable at any spatial scale from regional to microscopic. Spots are related in a purely spatial manner, and consequently, one spot can enclose multiple other spots that themselves contain other spots. In contrast, tags provide conceptual grouping of spots, allowing linkages between spots that are independent of their spatial position. The StraboSpot data system uses a graph database, rather than a relational database approach, to increase flexibility and to track geologically complex relationships. StraboSpot operates on two different platform types: (1) a field-based application that runs on iOS and Android mobile devices, which can function in either Internet-connected or disconnected environments; and (2) a web application that runs only in Internet-connected settings. We are presently engaged in incorporating microstructural data into StraboSpot, as well as expanding to include additional field-based (sedimentology, petrology) and lab-based (experimental rock deformation) data. The StraboSpot database will be linked to other existing and future databases in order to provide integration with other digital efforts in the geological sciences and allow researchers to do types of science that were not possible without easy access to digital data.

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We analyzed a catalog of 31 published earthquake chronologies to assess the commonality of quasiperiodic earthquake recurrence across a range of fault types and tectonic settings. The statistical approach we employ differs from previous methods in that it explicitly incorporates numeric uncertainties in the earthquake chronologies while recognizing that random sequences of events (against which the chronologies are tested) may appear to be less disordered over the short time scales typical of most published records. Our results show that 58% of the chronologies support an interpretation of quasiperiodic recurrence (probability of random recurrence < 10%). These include strike‐slip, normal, and reverse faults in both plate‐boundary and intraplate environments, which exhibit evidence for quasiperiodic recurrence with comparable frequency. We conclude that quasiperiodic failure is likely the norm for faults in the seismogenic crust and that stress renewal is a first‐order control on fault rupture across a wide range of tectonic settings.