48 research outputs found

    Shear behavior of DFDP-1 borehole samples from the Alpine Fault, New Zealand, under a wide range of experimental conditions

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    The Alpine Fault is a major plate-boundary fault zone that poses a major seismic hazard in southern New Zealand. The initial stage of the Deep Fault Drilling Project has provided sample material from the major lithological constituents of the Alpine Fault from two pilot boreholes. We use laboratory shearing experiments to show that the friction coefficient µ of fault-related rocks and their precursors varies between 0.38 and 0.80 depending on the lithology, presence of pore fluid, effective normal stress, and temperature. Under conditions appropriate for several kilometers depth on the Alpine Fault (100 MPa, 160 °C, fluid-saturated), a gouge sample located very near to the principal slip zone exhibits µ = 0.67, which is high compared with other major fault zones targeted by scientific drilling, and suggests the capacity for large shear stresses at depth. A consistent observation is that every major lithological unit tested exhibits positive and negative values of friction velocity dependence. Critical nucleation patch lengths estimated using representative values of the friction velocity-dependent parameter a−b and the critical slip distance D c , combined with previously documented elastic properties of the wall rock, may be as low as ~3 m. This small value, consistent with a seismic moment M o = ~4 × 1010 for an M w = ~1 earthquake, suggests that events of this size or larger are expected to occur as ordinary earthquakes and that slow or transient slip events are unlikely in the approximate depth range of 3–7 km

    Retrieving haystacks: a data driven information needs model for faceted search.

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    The research aim was to develop an understanding of information need characteristics for word co-occurrence-based search result filters (facets). No prior research has been identified into what enterprise searchers may find useful for exploratory search and why. Various word co-occurrence techniques were applied to results from sample queries performed on industry membership content. The results were used in an international survey of 54 practising petroleum engineers from 32 organizations. Subject familiarity, job role, personality and query specificity are possible causes for survey response variation. An information needs model is presented: Broad, Rich, Intriguing, Descriptive, General, Expert and Situational (BRIDGES). This may help professionals to more effectively meet their information needs and stimulate new needs, improving a systems ability to facilitate serendipity. This research has implications for faceted search in enterprise search and digital library deployments

    Control of style-of-faulting on spatial pattern of earthquake-triggered landslides

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    Predictive mapping of susceptibility to earthquake-triggered landslides (ETLs) commonly uses distance to fault as spatial predictor, regardless of style-of-faulting. Here, we examined the hypothesis that the spatial pattern of ETLs is influenced by style-of-faulting based on distance distribution analysis and Fry analysis. The Yingxiu–Beichuan fault (YBF) in China and a huge number of landslides that ruptured and occurred, respectively, during the 2008 Wenchuan earthquake permitted this study because the style-of-faulting along the YBF varied from its southern to northern parts (i.e. mainly thrust-slip in the southern part, oblique-slip in the central part and mainly strike-slip in the northern part). On the YBF hanging-wall, ETLs at 4.4–4.7 and 10.3–11.5 km from the YBF are likely associated with strike- and thrust-slips, respectively. On the southern and central parts of the hanging-wall, ETLs at 7.5–8 km from the YBF are likely associated with oblique-slips. These findings indicate that the spatial pattern of ETLs is influenced by style-of-faulting. Based on knowledge about the style-of-faulting and by using evidential belief functions to create a predictor map based on proximity to faults, we obtained higher landslide prediction accuracy than by using unclassified faults. When distance from unclassified parts of the YBF is used as predictor, the prediction accuracy is 80%; when distance from parts of the YBF, classified according to style-of-faulting, is used as predictor, the prediction accuracy is 93%. Therefore, mapping and classification of faults and proper spatial representation of fault control on occurrence of ETLs are important in predictive mapping of susceptibility to ETLs

    An adapted Clavien-Dindo scoring system in trauma as a clinically meaningful non-mortality endpoint

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    BACKGROUND: There is no consensus on reporting nonmortality trauma complications in a graded manner. The Clavien-Dindo scale of complications was originally for elective surgery and requires adaptation to provide meaningful data for trauma patients. In particular, the original score does not account for those treated without surgery. We report an adapted Clavien-Dindo in trauma (ACDiT) scale and apply it to patients managed operatively and nonoperatively. METHODS: A combined prospective and retrospective international multicenter observational study was undertaken to apply the ACDiT scale to 484 trauma patients at three university teaching hospitals (Birmingham, England (n = 303); Houston, Texas (n = 113); and Glasgow, Scotland (n = 68)). These included both intensive care unit (ICU) and non-ICU-managed patients. The Clavien-Dindo scoring system was adapted for trauma patients based on consensus amongst an international collaboration of trauma specialists at these sites. Data included whether initial patients were managed operatively or nonoperatively. Complication grades were compared with hospital-free and ICU-free days as other outcome measures of patient morbidity. RESULTS: Two hundred seventeen (44.8%) of 484 patients experienced complications, of whom 61 (28.1%) of 217 died (grade V). The remainder consisted of grades I (n = 20), II (n = 60), III (n = 24), and IV (n = 52). There was a strong association between higher ACDiT grade category and lower number of hospital-free and ICU-free days (p < 0.01). Eighty-eight patients with complications did not require surgery, validating the score's usefulness in patients managed nonoperatively. CONCLUSION: The ACDiT scale can be used to grade the severity of posttrauma complications in patients managed both operatively and nonoperatively. It provides clinically meaningful data for morbidity and mortality meetings and other quality improvement exercises. LEVEL OF EVIDENCE: Prognostic, level IV
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