The Magma Feeding System of the Klyuchevskaya Group of Volcanoes (Kamchatka)     

Gordeev  E. I.  Koulakov  I. Yu.  Shapiro  N. M. 《Doklady Earth Sciences》2020,493(2):627-631

Doklady Earth Sciences - Using observations from a large-scale seismic station network, we built a seismic tomography model of velocity anomalies for longitudinal (P-wave) and transverse (S-wave)...  相似文献   

Contributing Areas to Domestic Wells in Dipping Sedimentary Rocks under Extreme Recharge Events     

Claire R. Tiedeman  Allen M. Shapiro 《Ground water》2022,60(4):460-476

We use particle tracking to determine contributing areas (CAs) to wells for transient flow models that simulate cyclic domestic pumping and extreme recharge events in a small synthetic watershed underlain by dipping sedimentary rocks. The CAs consist of strike-oriented bands at locations where the water table intersects high-hydraulic conductivity beds, and from which groundwater flows to the pumping well. Factors that affect the size and location of the CAs include topographic flow directions, rock dip direction, cross-bed fracture density, and position of the well relative to streams. For an effective fracture porosity (n_e) of 10⁻⁴, the fastest advective travel times from CAs to wells are only a few hours. These results indicate that wells in this type of geologic setting can be highly vulnerable to contaminants or pathogens flushed into the subsurface during extreme recharge events. Increasing n_e to 10⁻³ results in modestly smaller CAs and delayed well vulnerability due to slower travel times. CAs determined for steady-state models of the same setting, but with long-term average recharge and pumping rates, are smaller than CAs in the models with extreme recharge. Also, the earliest-arriving particles arrive at the wells later in the steady-state models than in the extreme-recharge models. The results highlight the importance of characterizing geologic structure, simulating plausible effective porosities, and simulating pumping and recharge transience when determining CAs in fractured rock aquifers to assess well vulnerability under extreme precipitation events.  相似文献   

A revised evolutionary history of armadillos (Dasypus) in North America based on ancient mitochondrial DNA          下载免费PDF全文

Beth Shapiro  Russell W. Graham  Brandon Letts 《Boreas: An International Journal of Quaternary Research》2015,44(1):14-23

The large, beautiful armadillo, Dasypus bellus, first appeared in North America about 2.5 million years ago, and was extinct across its southeastern US range by 11 thousand years ago (ka). Within the last 150 years, the much smaller nine‐banded armadillo, D. novemcinctus, has expanded rapidly out of Mexico and colonized much of the former range of the beautiful armadillo. The high degree of morphological similarity between these two species has led to speculation that they might be a single, highly adaptable species with phenotypical responses and geographical range fluctuations resulting from environmental changes. If this is correct, then the biology and tolerance limits for D. novemcinctus could be directly applied to the Pleistocene species, D. bellus. To investigate this, we isolated ancient mitochondrial DNA from late Pleistocene‐age specimens of Dasypus from Missouri and Florida. We identified two genetically distinct mitochondrial lineages, which most likely correspond to D. bellus (Missouri) and D. novemcinctus (Florida). Surprisingly, both lineages were isolated from large specimens that were identified previously as D. bellus. Our results suggest that D. novemcinctus, which is currently classified as an invasive species, was already present in central Florida around 10 ka, significantly earlier than previously believed.  相似文献   

Numerical model of the submarine fresh-water discharge in a karst cavity     

N. B. Shapiro 《Physical Oceanography》2012,21(5):353-370

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Fluid-induced seismicity: Pressure diffusion and hydraulic fracturing   总被引：2，自引：0，他引：2  

S.A. Shapiro  C. Dinske 《Geophysical Prospecting》2009,57(2):301-310

Borehole fluid injections are common for the development of hydrocarbon and geothermic reservoirs. Often they induce numerous microearthquakes. Spatio-temporal dynamics of such induced microseismic clouds can be used to characterize reservoirs. However, a fluid-induced seismicity can be caused by a wide range of processes. Here we show that linear pore pressure relaxation and a hydraulic fracturing are two asymptotic end members of a set of non-linear diffusional phenomena responsible for seismicity triggering. To account for the whole range of processes we propose a rather general non-linear diffusional equation describing the pore pressure evolution. This equation takes into account a possibly strong enhancement of the medium permeability. Both linear pore pressure relaxation and hydraulic fracturing can be obtained as special limiting cases of this equation. From this equation we derive the triggering front of fluid induced seismicity, which is valid in the general case of non-linear pore pressure diffusion. We demonstrate corresponding seismicity signatures on different case studies.  相似文献   

Climate and coastal habitat change: a recipe for a dirtier ocean     

Shapiro K 《Marine pollution bulletin》2012,64(6):1079-1080

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Back front of seismicity induced by non‐linear pore pressure diffusion          下载免费PDF全文

Nicolas Hummel  Serge A. Shapiro 《Geophysical Prospecting》2016,64(1):170-191

Borehole fluid injections are accompanied by microseismic activity not only during but also after termination of the fluid injection. Previously, this phenomenon has been analysed, assuming that the main triggering mechanism is governed by a linear pressure diffusion in a hydraulically isotropic medium. In this context the so‐called back front of seismicity has been introduced, which allows to characterize the hydraulic transport from the spatiotemporal distribution of post‐injection induced events. However, rocks are generally anisotropic, and in addition, fluid injections can strongly enhance permeability. In this case, permeability becomes a function of pressure. For such situations, we carry out a comprehensive study about the behaviour and parametrization of the back front. Based on a model of a factorized anisotropic pressure dependence of permeability, we present an approach to reconstruct the principal components of the diffusivity tensor. We apply this approach to real microseismic data and show that the back front characterizes the least hydraulic transport. To investigate the back front of non‐linear pore‐fluid pressure diffusion, we numerically consider a power‐law and an exponential‐dependent diffusivity. To account for a post‐injection enhanced hydraulic state of the rock, we introduce a model of a frozen (i.e., nearly unchanged after the stimulation) medium diffusivity and generate synthetic seismicity. We find that, for a weak non‐linearity and 3D exponential diffusion, the linear diffusion back front is still applicable. This finding is in agreement with microseismic data from Ogachi and Fenton Hill. However, for a strong non‐linear fluid–rock interaction such as hydraulic fracturing, the back front can significantly deviate from a time dependence of a linear diffusion back front. This is demonstrated for a data set from the Horn River Basin. Hence, the behaviour of the back front is a strong indicator of a non‐linear fluid–rock interaction.  相似文献   

Vertical structure of the field of current velocities in the northwest part of the Black Sea based on the <Emphasis Type="Italic">LADCP</Emphasis> data for May 2004     

E. M. Lemeshko  A. N. Morozov  S. V. Stanichnyi  L. D. Mee  G. I. Shapiro 《Physical Oceanography》2008,18(6):319-331

The profiles of absolute current velocity obtained by using a lowered acoustic doppler current profiler (LADCP) are presented. In the course of the BSERP-3 expedition, the measurements were carried out in the regions of the Rim Current, anticyclonic eddy, and northwest shelf. In the core of the Rim Current, a unidirectional motion of waters is traced in layers below the main pycnocline down to depths greater than 500 m. Its characteristic velocity can be as high as 0.08 m/sec. It is shown that the direct action of the eddy is detected in the shelf region at distances larger than 20 km from the outer edge of the shelf in the zone bounded by an isobath of 100 m. The formation of multilayer vertical structures in the field of current velocities is revealed in the region of interaction of the anticyclonic eddy with irregularities of the bottom on the side of the shelf. A two-layer structure of currents with specific features in the layer of formed seasonal pycnocline is observed in the region of the shelf down to an isobath of 100 m. The profiles of the moduli of vertical shears of currents averaged over the casts ensemble are presented for the abyssal and shelf parts of the sea. It is shown that the shears induced by the geostrophic currents and wave processes in the region of the main pycnocline are comparable. Below the pycnocline, the shears are mainly determined by the wave processes. Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 25–37, November–December, 2008.  相似文献   

Solar Spectral Irradiance Variability in November/December 2012: Comparison of Observations by Instruments on the International Space Station and Models     

G. Thuillier  G. Schmidtke  C. Erhardt  B. Nikutowski  A. I. Shapiro  C. Bolduc  J. Lean  N. Krivova  P. Charbonneau  G. Cessateur  M. Haberreiter  S. Melo  V. Delouille  B. Mampaey  K. L. Yeo  W. Schmutz 《Solar physics》2014,289(12):4433-4452

Onboard the International Space Station (ISS), two instruments are observing the solar spectral irradiance (SSI) at wavelengths from 16 to 2900 nm. Although the ISS platform orientation generally precludes pointing at the Sun more than 10?–?14 days per month, in November/December 2012 a continuous period of measurements was obtained by implementing an ISS ‘bridging’ maneuver. This enabled observations to be made of the solar spectral irradiance (SSI) during a complete solar rotation. We present these measurements, which quantify the impact of active regions on SSI, and compare them with data simultaneously gathered from other platforms, and with models of spectral irradiance variability. Our analysis demonstrates that the instruments onboard the ISS have the capability to measure SSI variations consistent with other instruments in space. A comparison among all available SSI measurements during November–December 2012 in absolute units with reconstructions using solar proxies and observed solar activity features is presented and discussed in terms of accuracy.  相似文献   

Photoevaporation of cosmological minihaloes during reionization   总被引：1，自引：0，他引：1  

Paul R. Shapiro  Ilian T. Iliev †  Alejandro C. Raga 《Monthly notices of the Royal Astronomical Society》2004,348(3):753-782

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