Forward induced seismic hazard assessment: application to a synthetic seismicity catalogue from hydraulic stimulation modelling     

Amir Hossein Hakimhashemi  Jeoung Seok Yoon  Oliver Heidbach  Arno Zang  Gottfried Grünthal 《Journal of Seismology》2014,18(3):671-680

The M _w 3.2-induced seismic event in 2006 due to fluid injection at the Basel geothermal site in Switzerland was the starting point for an ongoing discussion in Europe on the potential risk of hydraulic stimulation in general. In particular, further development of mitigation strategies of induced seismic events of economic concern became a hot topic in geosciences and geoengineering. Here, we present a workflow to assess the hazard of induced seismicity in terms of occurrence rate of induced seismic events. The workflow is called Forward Induced Seismic Hazard Assessment (FISHA) as it combines the results of forward hydromechanical-numerical models with methods of time-dependent probabilistic seismic hazard assessment. To exemplify FISHA, we use simulations of four different fluid injection types with various injection parameters, i.e. injection rate, duration and style of injection. The hydromechanical-numerical model applied in this study represents a geothermal reservoir with preexisting fractures where a routine of viscous fluid flow in porous media is implemented from which flow and pressure driven failures of rock matrix and preexisting fractures are simulated, and corresponding seismic moment magnitudes are computed. The resulting synthetic catalogues of induced seismicity, including event location, occurrence time and magnitude, are used to calibrate the magnitude completeness M _c and the parameters a and b of the frequency-magnitude relation. These are used to estimate the time-dependent occurrence rate of induced seismic events for each fluid injection scenario. In contrast to other mitigation strategies that rely on real-time data or already obtained catalogues, we can perform various synthetic experiments with the same initial conditions. Thus, the advantage of FISHA is that it can quantify hazard from numerical experiments and recommend a priori a stimulation type that lowers the occurrence rate of induced seismic events. The FISHA workflow is rather general and not limited to the hydromechanical-numerical model used in this study and can therefore be applied to other fluid injection models.  相似文献   

Discussion of the Paper ‘Late Pan-African Magmatism and Crustal Development in Northeastern Egypt’     

Robert J. Stern  David Gottfried 《Geological Journal》1989,24(4):371-374

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Spurenelementgehalt der Saale – ein Vergleich der Analysenergebnisse aus den Jahren 1950 und 1996     

G. Proft  W. Schrn 《Chemie der Erde / Geochemistry》2008,68(2):221-233

Thirty four elements dissolved in water and 33 elements bound in particulate matter were analysed in the small river Saale (Thuringia, Germany, MQ=23 m³/s) in 1996 and the results were compared with those obtained in 1950 (44 elements). Monthly sampling was used to eliminate fluctuations caused by seasons and weather. Comparison of the element contents of a river over a 40-year-time span provides interesting insight into the anthropogenic change in the catchment area of the river with regard to „global change”.Without taking into consideration systematic errors, the analysed elements can be divided into three groups:

(a) Elements whose average annual analytical values in 1996 were lower by >50% than those in 1950: Al, As, Ba, Fe, Pb, Zn (in solution), and As, B, Cr, Li, Mn, Pb, Se, Sn, U (suspended).

(b) Elements whose average annual analytical values in 1996 are in the range of those in 1950, i.e., are within 50–150%: Ca, Co, Cr, F, K, Li, Mn, Na, Si, Sr, Ti, U (in solution), and Hg, Cr, Cu, Sc, Sr, Ti, Zn (suspended).

(c) Elements whose average annual analytical values in 1996 were higher by >150% than those in 1950: B, Cd, Mg, Ni, Rb, Sc (in solution), and Ba, Ni, P, Zr (suspended).

The increases in the element concentrations are not only caused by wastewater. Acid rain and fertilizer affect the pH and the electrolyte status of soils and cause mobilization of elements. This can be a reason for the increase in the alkalies and alkaline earth. For most elements are higher and lower values were found in 1996 and are only partly caused by systematic errors in the methods used in 1950. Taking into consideration of the natural fluctuations some element values 1996 equal or are lower (Tabelle 10 and 12). Because of the 100–200% RSD (12 samples per year), it is almost impossible to decide whether the deviations are due to analytical errors or to natural causes. The bound part of the elements is considered to be the suspended portion (seston=particulate matter) and, for one and the same element the suspended portion is equal or higher than the portion in solution. In the case of natural plant stock in the catchment area, the erosion is small. The increase in farming caused a higher soil erosion in the river. Storm precipitation causes short-term (1–2 h) peaks in the suspended load with values 2–3 orders of magnitude higher. In the case of monthly sampling, such peaks are unlikely to be detected. This produces values of suspended loads that tend to be too small. Increases of the bounded elements together with the elements in solution cause increases of eutrophication in the ocean.The contents of elements transported in solution and in particulate form in the river Saale are not equal to the element contents of the upper earth crust. Weathering and the fluviatil element transport cause a fractionation of the thallassophile (enriched in ocean) and therraphile elements (enriched in continents). Thallassophile elements are Mg, Ca, Sr, B, As, U, Sn, Cd, Zn, Se (transported in solution) and U, Cr, Li, B, Ba, Se, Mn, Cu, P, Sn, Cd, Rb, Pb, S and Zn (transported in seston) and therraphile elements are Cs, Co, Sc, Ni, Ti, Fe, Al, and K. As a result a fractionation in thallassophile and therraphile elements results and influences the geochemical cycles like magmatic differentiations.  相似文献   

Fractionation of palladium and platinum in a Mesozoic diabase sheet, Gettysburg basin, Pennsyvania: implications for mineral exploration     

David Gottfried  A.J. Froelich  Norma Rait  P.J. Aruscavage 《Journal of Geochemical Exploration》1990,37(1)

The York Haven diabase sheet displays clear-cut evidence of fractionation of Pd and Pt during differentiation of a high-Ti (about 1.1%) quartz-normative tholeiitic magma (York Haven type). At York Haven the sheet is about 750 m thick. It is characterized by abundant cumulus MgO-rich orthopyroxene (bronzite), and is markedly depleted in incompatible elements relative to the chilled margins. In contrast, at Reesers Summit, 16 km to the northwest, the sheet is about 500 m thick and consists of evolved rocks that have contents of incompatible elements two to three times greater than in the enclosing chilled margins. These evolved rocks represent complementary fractions to the cumulate rocks at York Haven. Mineralogic, petrologic and geochemical variations suggest considerable lateral migration and fractionation of the initial magma.Chilled margins of both sections have essentially the same Pd and Pt contents (10 ppb each) and similar Pd to Pt ratios (1.2). During differentiation, the cumulate rocks at York Haven were enriched in Pt and depleted in Pd, whereas at Reesers Summit, the low-MgO diabase and ferrogabbro zone were enriched in Pd relative to Pt. Anomalously high contents of Pd (to 165 ppb), Au (to 54 ppb), and Te (to 26 ppb) were found in an iron- (to 18%) and chlorine- (to 0.44%) rich ferrogabbro at Reesers Summit, suggesting possible late or post-magmatic enrichment of precious metals. Field relations, geochemical and petrographic data provide guides for further exploration for Pd and Pt in differentiated high-Ti quartz-normative diabase sheets. Based on present information, the most favorable sites for economic deposits are late-stage differentiates enriched in Fe and Cl.  相似文献   

Limnologie und Medizin     

Gottfried Huber-Pestalozzi 《Aquatic Sciences - Research Across Boundaries》1949,11(1-2):1-14

Ohne Zusammenfassung  相似文献   

Aspects of the magmatic geochemistry of bismuth     

L.P. Greenland  D. Gottfried  E.Y. campbell 《Geochimica et cosmochimica acta》1973,37(2):283-295

Bismuth has been determined in 74 rocks from a differentiated tholeiitic dolerite, two calc-alkaline batholith suites and in 66 mineral separates from one of the batholiths. Average bismuth contents, weighted for rock type, of the Great Lake (Tasmania) dolerite, the Southern California batholith and the Idaho batholith are, 32, 50 and 70 ppb respectively. All three bodies demonstrate an enrichment of bismuth in residual magmas with magmatic differentiation. Bismuth is greatly enriched (relative to the host rock) in the calcium-rich accessory minerals, apatite and sphene, but other mineral analyses show that a Bi-Ca association is of little significance to the magmatic geochemistry of bismuth. Most of the bismuth, in the Southern California batholith at least, occurs in a trace mineral phase (possibly sulfides) present as inclusions in the rock-forming minerals.  相似文献   

Boundary-layer observations over water and arctic sea-ice during on-ice air flow     

Burghard Brümmer  Birgit Busack  Heinrich Hoeber  Gottfried Kruspe 《Boundary-Layer Meteorology》1994,68(1-2):75-108

Observations made on 8 and 9 May 1988 by aircraft and two ships in and around the marginal ice zone of the Fram Strait during on-ice air flow under cloudy and cloud-free conditions are presented.The thermodynamic modification of the air mass moving from the open water to the ice over horizontal distances of 100–300 km is only a few tenth of a degree for temperature and a few tenth of a gram per kilogram for specific humidity. This is due to the small temperature differences between sea and ice surfaces. During the day, the ice surface is even warmer than the sea surface. The stably stratified 200–400 m deep boundary layer is often topped by a moisture inversion leading to downward fluxes of sensible as well as latent heat.The radiation and energy balance at the surface are measured as functions of ice cover, cloud cover and sun elevation angle. The net radiationR _Nis the dominating term of the energy budget. During the day, the difference ofR _Nbetween clear and overcast sky is only a few W/m² over ice, but 100–200 W/m² over water. During the night,R _Nover ice is more sensitive to cloud cover.The kinematic structure is characterized by strong shears of the longitudinal and the transversal wind component. The profile of the latter one shows an inflection point near the top of the boundary layer. Dynamically-driven roll circulations are numerically separated from the mean flow. The secondary flow patterns have wavelengths of about 1 km and contribute substantially to the total variances and covariances.  相似文献   

Theoretical aspects of coal washer performance     

Stanislaw Cierpisz  Byron S. Gottfried 《International Journal of Mineral Processing》1977,4(3):261-278

This paper presents a theoretical analysis of the performance of ideal float-and-sink type coal washing devices. Included are studies of single washer performance, single washer with bypass, multiple washers in parallel and multiple washers in series. A maximum yield principle is developed for the cases of a single washer with bypass and multiple washers in parallel. The results of numerical calculations for actual washers are also presented and compared with the theoretical predictions for multiple washers in parallel and multiple washers in series.  相似文献   

Ein Beitrag zur Bestimmung von partikulärem organischen Kohlenstoff in Wasserproben     

G. Proft 《洁净——土壤、空气、水》1983,11(6):631-636

The method after Strickland and Parsons is modified for fresh water as follows: filtration on glass-fibre paper, oxidation with K₂Cr₂O₇ in cone. H₂SO₄ for 2 h at 130 °C, dilution to 2.5 times the volume by aqua dest., centrifuging-off of the turbidity and extinction measurement at 445 nm against the blank value, the sample solution being balanced to the transmission of 100% (extinction = 0). Here, the following calibration line holds for the concentration C and the quantity of oxidation solution Ox: C = E_1cmc · 0.162 · Ox, C in mg filter. The oxidation solution contains 4.8 g K₂Cr₂O₇ as dissolved in 20 ml aqua dest. and made up with conc. H₂SO₄ to 11. With 5 ml of this solution one is able to determine 0.05 … 1 mg C/filter. Calibration is performed with 125 mg/l glucose solution. Comparative investigations have shown a good agreement with elementary-analytically obtained measured values. The occurring errors have been determined mainly by sampling. In the range of very small values we have to take into account a blank value of the filter due to the adsorption of dissolved organic substances on the filter.  相似文献   

USGS SOLICITS DATA FOR THREE NEWSAMPLES     

F. J. Flanagan  David Gottfried 《Geostandards and Geoanalytical Research》1978,2(2):211-211

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