Seismic tomography and deformation modeling of the junction of the San Andreas and Calaveras faults

Local earthquake P traveltime data is inverted to obtain a three‐dimensional tomographic image of the region centered on the junction of the San Andreas and Calaveras faults. The resulting velocity model is then used to relocate more than 17,000 earthquakes and to produce a model of fault structure in the region. These faults serve as the basis for modeling the topography using elastic dislocation methods. The region is of interest because active faults join, it marks the transition zone from creeping to locked fault behavior on the San Andreas fault, it exhibits young topography, and it has a good spatial distribution of seismicity. The tomographic data set is extensive, consisting of 1445 events, 96 stations, and nearly 95,000 travel time readings. Tomographic images are resolvable to depths of 12 km and show significant velocity contrasts across the San Andreas and Calaveras faults, a low‐velocity zone associated with the creeping section of the San Andreas fault, and shallow low‐velocity sediments in the southern Santa Clara valley and northern Salinas valley. Relocated earthquakes only occur where vp > 5 km/s and indicate that portions of the San Andreas and Calaveras faults are non vertical, although we cannot completely exclude the possibility that all or part of this results from ray tracing problems. The new dips are more consistent with geological observations that dipping faults intersect the surface where surface traces have been mapped. The topographic modeling predicts extensive subsidence in regions characterized by shallow low‐velocity material, presumably the result of recent sedimentation. Some details of the topography at the junction of the San Andreas and Calaveras faults are not consistent with the modeling results, suggesting that the current position of this “triple junction” has changed with time. The model also predicts those parts of the fault subject to contraction or extension perpendicular to the fault strike and hence the sense of any dip‐slip component. In each locality the relative vertical motion across the fault is consistent with the fault dips found with the new hypocentral locations

Geodetic evidence for interconnectivity between Aira and Kirishima magmatic systems, Japan

It is not known whether clustered or aligned volcanic edifices at the Earth surface have connected magmatic systems at depth. Previously suggested by geological records of paired eruptions, volcano interconnectivity still lacks proper geodetic evidence. Here we use GPS time-series and deformation modeling to show how Aira caldera and Kirishima, two adjacent volcanic centers in Kagoshima graben (southern Japan), interacted during Kirishima unrest in 2011. Whereas Aira caldera had been inflating steadily for two decades, it deflated during the eruption of Kirishima which started with a large-volume lava extrusion. This deflation, which cannot be explained by stress changes, is interpreted as the result of magma withdrawal from the Aira system during the Kirishima replenishment phase. This study highlights the behavior of connected neighboring volcanic systems before and after a large eruption, and the importance of taking into account volcano interactions in eruption probability models

Measuring large topographic change with InSAR: lava thicknesses, extrusion rate and subsidence rate at Santiaguito volcano, Guatemala

Lava flows can produce changes in topography on the order of 10s-100s of metres. A knowledge of the resulting volume change provides evidence about the dynamics of an eruption. We present a method to measure topographic changes from the differential InSAR phase delays caused by the height differences between the current topography and a Digital Elevation Model (DEM). This does not require a pre-event SAR image, so it does not rely on interferometric phase remaining coherent during eruption and emplacement. Synthetic tests predicts that we can estimate lava thickness of as little as �9 m, given a minimum of 5 interferograms with suitably large orbital baseine separations. In the case of continuous motion, such as lava flow subsidence, we invert interferometric phase simultaneously for topographic change and displacement. We demonstrate the method using data from Santiaguito volcano, Guatemala, and measure increases in lava thickness of up to 140 m between 2000 and 2009, largely associated with activity between 2000 and 2005. We find a mean extrusion rate of 0.43 +/- 0.06 m3/s, which lies within the error bounds of the longer term extrusion rate between 1922-2000. The thickest and youngest parts of the flow deposit were shown to be subsiding at an average rate of �-6 cm/yr. This is the first time that flow thickness and subsidence have been measured simultaneously. We expect this method to be suitable for measurment of landslides and other mass flow deposits as well as lava flows

Intestinal motility distal of a deviating ileostomy after rectal resection with the construction of a primary anastomosis:results of the prospective COLO-MOVE study

Purpose No consensus exists regarding the use of preoperative bowel preparation for patients undergoing a low anterior resection (LAR). Several comparative studies show similar outcomes when a single time enema (STE) is compared with mechanical bowel preparation (MBP). It is hypothesized that STE is comparable with MBP due to a decrease in intestinal motility distal of a newly constructed diverting ileostomy (DI). Methods In this prospective single-centre cohort study, patients undergoing a LAR with primary anastomosis and DI construction were given a STE 2 h pre-operatively. Radio-opaque markers were inserted in the efferent loop of the DI during surgery, and plain abdominal X-rays were made during the first, third, fifth and seventh postoperative day to visualize intestinal motility. Results Thirty-nine patients were included. Radio-opaque markers were situated in the ileum or right colon in 100%, 100% and 97.1% of the patients during respectively the first, third and fifth postoperative day. One patient had its most distal marker situated in the left colon during day five. In none of the patients, the markers were seen distal of the anastomosis. Conclusion Intestinal motility distally of the DI is decreased in patients who undergo a LAR resection with the construction of an anastomosis and DI, while preoperatively receiving a STE

Detectable contributions of colloids to soil P and C content in arid and hyperarid region of the Atacama (Chile)

Atacama Desert is mainly known as the driest place on Earth where life has been developed under arid to hyper arid conditions since Oligocene-Miocene. Therefore, soils of Atacama contain fingerprints of past and present life which might be used as an analog to study the evolution of life under equivalent arid conditions, like Mars. In this study, we quantify the colloidal phosphorus and carbon distribution in the first 10 cm of soil profile along an altitudinal transect. Samples were taken along a transect in the region of Quebrada Aroma spanning from the arid Percordillera of the Andes (2720 m a.s.l.) towards the hyper arid core of the desert (1340 m a.s.l.). Water dispersible colloids (WDC) were separated and measured using the field-flow-field fractionation (FFF) method and subsequently their Corg and P content were characterized and quantified by detectors (DLS, ICP-MS, UV, OCD, fluorescence). Data was compared to total C, P and (available) Olsen-P also measured in the samples. The Olsen-P (available-P) varied within the Aroma transect from ca. 2 to 8 mg P kg-1, but was not related to either altitude or depth in the upper soil (0-10 cm). Colloidal P contents ranged from <0.1 to 4 mg P kg-1 soil, with increasing trend from low to higher elevations. Thereby, suggesting an increasing proportion of the available P potential being present in the WDC fraction. The Colloidal Corg content of the Aroma transect did range from 65 to 90 (for sites 2020 to 1340m) and 110 mg Corg kg-1 soil WDC (2720 m). Colloidal Corg content as a function of the altitude showed a similar trend to the Corg content of the soils: the highest colloidal Corg content was found at 2720 m. The proportion of soil Corg within the colloidal fraction was up to 6% of the bulk soil organic matter (OM) content, as the OM content was intensively enriched in the colloidal fraction. Further quantification of phosphorus and carbon content in WDC in deeper part of soil is required to obtain a more comprehensive view of role of colloidal inputs and dynamics in the Atacama Desert

Richness of termite genera in a semi-arid region (Sertão) in NE Brazil (Isoptera)

The genus richness of the termite fauna of a semiarid area (caatinga) in Northeastern Brazil was investigated in the dry season of 1996 and the rainy season of 1998. Eight genera belonging to three termite families (Termitidae, Rhinotermitidae and Kalotermitidae) were found in assessments of termite nests and mounds, investigation of dead wood, and cardboard baits buried 10 cm deep in the soil. The nestbuilder guild was represented by only three genera: Nasutitermes, Constrictotermes and Microcerotermes. Their density (about 1-3 nests ha-1) was very low. In mounds of Constrictotermes, the genus Inquilinitermes is almost invariably found as an inquiline. During the dry season of 1996, wood-inhabiting Kalotermitidae (Neotermes sp.) were abundant in dead branches still attached to the trees. In dead wood on the ground we recorded Heterotermes of the Rhinotermitidae, and Amitermes and Termes of the Termitidae. A relatively high activity of Heterotermes on the baits was recorded within 3 months of exposure. Thus, this site is characterized by a very low genus diversity of termites; nest builders are rare, but soil- and wood-dwelling species are highly active in spite of the adverse conditions (drought) which reign during the larger part of the year

System Test of the ATLAS Muon Spectrometer in the H8 Beam at the CERN SPS

An extensive system test of the ATLAS muon spectrometer has been performed in the H8 beam line at the CERN SPS during the last four years. This spectrometer will use pressurized Monitored Drift Tube (MDT) chambers and Cathode Strip Chambers (CSC) for precision tracking, Resistive Plate Chambers (RPCs) for triggering in the barrel and Thin Gap Chambers (TGCs) for triggering in the end-cap region. The test set-up emulates one projective tower of the barrel (six MDT chambers and six RPCs) and one end-cap octant (six MDT chambers, A CSC and three TGCs). The barrel and end-cap stands have also been equipped with optical alignment systems, aiming at a relative positioning of the precision chambers in each tower to 30-40 micrometers. In addition to the performance of the detectors and the alignment scheme, many other systems aspects of the ATLAS muon spectrometer have been tested and validated with this setup, such as the mechanical detector integration and installation, the detector control system, the data acquisition, high level trigger software and off-line event reconstruction. Measurements with muon energies ranging from 20 to 300 GeV have allowed measuring the trigger and tracking performance of this set-up, in a configuration very similar to the final spectrometer. A special bunched muon beam with 25 ns bunch spacing, emulating the LHC bunch structure, has been used to study the timing resolution and bunch identification performance of the trigger chambers. The ATLAS first-level trigger chain has been operated with muon trigger signals for the first time

Multi-criteria assessment of household preferences for reducing greenhouse gas emissions: an analysis of household survey data from four European cities

In a study of households living in mid-size cities in France, Germany, Norway and Sweden we assessed preferences (among 65 possible actions) for reducing greenhouse gas (GHG) emissions. Each GHG reduction action was compared in terms of three objective criteria – CO2e emissions, health impact and cost – using scores which gave alternative priority weightings to each. The multi-criteria scores were then compared with the proportion of respondents declaring their willingness to implement each action. Actions that respondents were often willing to implement and scored highly on the three assessment criteria included measures with likely ancillary benefits for health such as eating 30% more vegetarian food, walking and cycling instead of using public transport, and improvements of roof and window insulation. Although most householders appeared willing to make appreciable changes to their lifestyle and home in order to help achieve GHG emissions reductions, relatively few signaled their willingness to adopt major changes, such as becoming entirely vegetarian or giving up use of the car, even if there were appreciable health benefits. The evidence of these analyses provides insights into household preferences for actions that may help achieve important mitigation and health benefits

Einfluss der Eindeichung auf Pestizidrückstände in Böden eines landwirtschaftlichen Gebietes des Red River Deltas, Vietnam

Fruchtbare Böden und eine hohe Verfügbarkeit von Wasser machen Deltaregionen zu den wichtigsten landwirtschaftlichen Produktionsflächen. Zur Sicherstellung hoher Erträge werden insbesondere in Reismonokulturen, Pestizide in einer erhöhten Menge und Häufigkeit eingesetzt. Während das Verhalten dieser Stoffe im Nassreisanbau bereits in früheren Studien beschrieben wurde, hat diese Studie zum Ziel den Einfluss von Deich-Konstruktionen auf die räumliche Verteilung der Pestizide zu untersuchen. Dazu wurden Boden- und Sedimentproben im Delta des Roten Flusses im Landkreis Giao Thuy entnommen. Dieses Gebiet ist von einem Meer- und Flussdeich mit verschiedenen Einlass- und Abflussschleusen umgeben. Dadurch findet eine Regulation der Wasserbewirtschaftung statt und das eingedeichte Gebiet wird vor Überschwemmung, Stürmen und das Eindringen von Salzwasser geschützt. In der Vergangenheit beobachteten regionale Behörden eine Abnahme der Wasserqualität vom Flussdeich hin zum Meerdeich. Dies ist vermutlich auf einen verringerten Wasseraustausch zurückzuführen, hervorgerufen durch das Deichsystem, was zu einer Akkumulation der Pestizidrückstände innerhalb des eingedeichten Gebietes führt. Um diese Hypothese zu prüfen, wurden Boden- und Sedimentproben von Reisflächen, Bewässerungsgräben und auch von Salzwasseraquakulturflächen außerhalb des eingedeichten Gebietes entnommen und anschließend auf Rückstände von 12 verschiedenen Pestiziden hin untersucht. Die Pestizide wurden wie folgt bestimmt: Extraktion mittels accelerated solvent extraction (ASE), gefolgt von einer Aufreinigung nach Laabs et al. (2007) und der Quantifizierung mittels Gaschromatographie gekoppelt an ein Massenspektrometer (GC-MS). Vorläufige Ergebnisse lassen vermuten, dass Chlorpyrifos, Propiconazole und Isoprothiolane häufig in den Proben der Reisflächen vorhanden sind. In Reisflächen nahe des Meerdeiches wurden keine erhöhten Pestizidkonzentrationen ermittelt. Die Pestizidrückstände in den Proben der Reisflächen sind eher der direkten Applikation verschuldet, wohingegen die Kanalproben keiner direkten Applikation ausgesetzt sind