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

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

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

The timing of gold mineralization across the eastern Yilgarn craton using U–Pb geochronology of hydrothermal phosphate minerals

The highly mineralized Eastern Goldfields of the eastern Yilgarn craton is an amalgamation of dominantly Neoarchaean granitoid-greenstone terranes and domains that record a history of early rifting, followed by westward directed collision with initial arc formation, collision and clastic basin formation, and final accretion to the western Yilgarn proto-craton between 2.66 and 2.60 billion years ago. The gold deposits that define this region as a world-class gold province are the product of orogenic processes that operated during accretion late in the tectonic history, after initial compressional deformation (D1–D2) and the majority of granitoid magmatism. Minor gold was also deposited throughout the entire tectonic history in magmatic-hydrothermal-related systems. However, such mineralization (mostly < 0.3 g/t gold) is nowhere economic unless it overprints, or is overprinted by, much higher-grade orogenic gold lodes.Robust SHRIMP U–Pb geochronology of gold-related hydrothermal xenotime and monazite supports structural studies that gold mineralization occurred during late transpressional events (D3–D4), shortly before cratonization. However, westward migration of collision and accretion produced a complementary diachroneity in the timing of gold mineralization of 5 to 20 m.y. between c. 2.65 Ma in the east (including Laverton District, Kurnalpi Terrane) to c. 2.63 Ma in the west (including Kalgoorlie Terrane) across the eastern part of the craton. The robust geochronology refutes previous suggestions that significant gold mineralization events extended from DE to D4 in the evolution of the orogen and that the Kalgoorlie gold deposits formed over a period of 45 m.y. The crustal continuum model is applicable within terranes where orogenic gold depositional events were penecontemporaneous, but must be modified to account for diachroneity of orogenic events and gold mineralization across the Eastern Goldfields