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991.
3D coseismic Displacement of 2010 Darfield, New Zealand earthquake estimated from multi-aperture InSAR and D-InSAR measurements 总被引:1,自引:1,他引:1
Differential interferometric synthetic aperture radar (D-InSAR) measures ground deformation only along the line-of-sight (LOS) of the radar, which limits the capability of D-InSAR in investigating the surface damages and the focus mechanisms of earthquakes. We do a three-dimensional (3D) decomposition of the coseismic displacement of the Darfield, New Zealand earthquake that occurred on 3 September 2010 by exploiting the Multi-Aperture InSAR (MAI) and D-InSAR measurements from both ascending and descending L-band PALSAR data. Due to the dispersive nature of the ionosphere and the slight Doppler shift between the forward- and backward-looking interferograms, the ionospheric effects can be more serious in MAI measurements than in D-InSAR. We propose mitigating the ionospheric effects in the MAI processing with the directional filtering and interpolation procedure that has been applied in Offset-tracking. The rupture revealed by the 3D surface displacement fits closely to the Greendale fault, which is believed to be responsible for the earthquake. The horizontal ground motions, mostly eastwards in the hanging wall and westwards in the footwall, reached up to 2.5 m and are anti-symmetric with respect to the Greendale fault. Up to 2.5 m subsidence occurred in the hanging wall, while uplift is found in the footwall with an extreme case of 1.6 m in the far left of the fault. This makes us conclude that the Greendale fault is a normal and dextral strike-slip. It is seen that the MAI measurements are very helpful in the derivation of 3D coseismic displacement fields as it provides more accurate displacement estimation in the north–south direction. 相似文献
992.
A preliminary commission error analysis whereby orbit perturbation theory and other techniques are used to assess and predict the recovery of the Earths gravity field from the challenging microsatellite payload (CHAMP) mission is developed and implemented. With CHAMP launched in July 2000, accumulated evidence is now available to quantify the errors in the recovery procedure including the orbital precision from GPS, attitude errors, accelerometer noise and thruster mismatch/misalignment. For the latter, numerical integrations using a variable length single-step Runge–Kutta integrator and a fixed length multi-step method are compared to assess the error associated with assuming that the thruster misalignment can be spread uniformly across a step interval. Error degree variances from simulated studies are compared to results from a recently released CHAMP-based gravity field, EIGEN-1S. It is seen that the orbital positioning, as derived from the onboard GPS receiver, is critical, with accelerometer noise contributing at a lower level. Attitude error, at currently quoted accuracy, is not significant as an error source.
AcknowledgementsThe authors would like to thank the UK Natural Environment Research Council (Grant No. NER/A/0000/00612) for financing this study and GFZ for supplying the data and technical support. 相似文献
993.
Muriel Z.M. Brückner Christian Schwarz Giovanni Coco Anne Baar Márcio Boechat Albernaz Maarten G. Kleinhans 《地球表面变化过程与地形》2021,46(6):1128-1144
Sediment-stabilizing and -destabilizing organisms, i.e. microphytobenthos (biofilms) and macrozoobenthos (bioturbators), affect the erodibility of muddy sediments, potentially altering large-scale estuarine morphology. Using a novel eco-morphodynamic model of an idealized estuary, we investigate eco-engineering effects of microphytobenthos and two macrozoobenthic bioturbators. Local mud erodibility is based on species pattern predicted through hydrodynamics, soil mud content, competition and grazing. Mud resuspension and export is enhanced under bioturbation and prevented under biostabilization through respective exposure and protection of the supra- and intertidal. Bioturbation decreases mud thickness and bed elevations, which increases net mud fluxes. Microphytobenthos reduces erosion, leading to a local mud increase of intertidal sediments. In multi-species scenarios, an effective mud-prone bioturbator strongly alters morphology, exceeding that of a more abundant sand-prone moderate species, showing that morphological change depends on species traits as opposed to abundance. Altering their habitat, the effective mud-prone bioturbator facilitates expansion of the sand-prone moderate bioturbator. Grazing and species competition favor species distributions of dominant bioturbators. Consequently, eco-engineering affects habitat conditions while species interactions determine species dominance. Our results show that eco-engineering species determine the mud content of the estuary, which suggests large effects on the morphology of estuaries with aggravating habitat degradation. 相似文献
994.
M. A. Mishkin A. M. Lennikov T. B. Bayanova G. M. Vovna V. G. Sakhno R. A. Oktyabr’sky Z. G. Badredinov 《Russian Journal of Pacific Geology》2010,4(3):223-227
This paper reports the first U-Pb geochronological data on the Precambrian granitoids of the Batomga block (Aldan shield).
It was established that the amphibole diorites of this block have an age of 2062 ± 14 Ma, while biotite granites are dated
at 2055 ± 7 Ma. These granitoids were subjected to epidote-amphibolie facies metamorphism 1920 ± 8 Ma ago. 相似文献
995.
Professor Dr. Kurt Spangenberg Z. Heidenheim 《Contributions to Mineralogy and Petrology》1949,1(5-6):529-535
Ohne ZusammenfassungAbgeschlossen iiim Juni 1947. 相似文献
996.
N. I. Izhovkina A. T. Karpachev I. S. Prutensky S. A. Pulinets Z. Klos H. Rotkel 《Geomagnetism and Aeronomy》2009,49(8):1254-1256
It has been indicated that the spectrum of electrostatic waves in the ionospheric plasma depends on the geophysical conditions
and solar wind parameters. The wave field measurements in the frequency band 0.1–10 MHz in the topside ionosphere were used
to analyze the electrostatic instabilities of the plasma electron content (the APEX satellite experiment). A change of the
sign of one magnetic field component at the geomagnetic equator can result in the formation of the large-scale irregular plasma
structure with a decay of the natural electrostatic oscillations and vortices in unstable plasma. The plasma particle polarization
drift from the region of decay of electrostatic oscillations and vortices can cause large plasma density and temperature gradients
across the geomagnetic field. New vortices can originate at these gradients. This mechanism of plasma vortex formation and
decay can be important for mass and energy convection in the topside ionosphere. 相似文献
997.
Z. J. Kabala H. K. El-Sayegh H. P. Gavin 《Stochastic Environmental Research and Risk Assessment (SERRA)》2002,16(6):399-424
Logarithmic sensitivities and plausible relative errors are studied in a simple no-crossflow model of a transient flowmeter
test (TFMT). This model is identical to the model of a constant-rate pumping test conducted on a fully penetrating well with
wellbore storage, surrounded by a thick skin zone, and situated in a homogeneous confined aquifer. The sensitivities of wellbore
drawdown and wellface flowrate to aquifer and skin parameters are independent of the pumping rate. However, the plausible
relative errors in the aquifer and skin parameters estimated from drawdown and wellface flowrate data can be proportionally
decreased by increasing the pumping rate. The plausible relative errors vary by many orders of magnitude from the beginning
of the TFMT. The practically important flowrate and drawdown measurements in this test, for which the plausible relative errors
vary by less than one order of magnitude from the minimum plausible relative errors, can begin approximately when the dimensionless
wellface flowrate exceeds q
D
=q/Q≈0.4. During most of this stage of the test, the plausible relative errors in aquifer hydraulic conductivity (K
a
) are generally an order of magnitude smaller than those in aquifer specific storativity. The plausible relative errors in
the skin hydraulic conductivity (K
s
) are generally larger than the plausible relative errors in the aquifer specific storativity when the thick skin is normal
(K
s
>K
a
) and smaller when the thick skin is damaged (K
s
<K
a
). The specific storativity of the skin zone would be so biased that one should not even attempt to estimate it from the TFMT.
We acknowledge Wiebe H. van der Molen for recommending the De Hoog algorithm and sharing his code. This research was partially
supported by the US Geological Survey, USGS Agreement #1434-HQ-96-GR-02689 and North Carolina Water Resources Research Institute,
WRRI Project #70165. 相似文献
998.
Analysis of the 16S-23S rDNA intergenic spacers (IGSs) of marine vibrios for species-specific signature DNA sequences 总被引:7,自引:0,他引:7
Vibrios are widespread in the marine environment and a few pathogenic species are known to be commonly associated with outbreaks of diarrheal diseases in humans due to the consumption of raw or improperly cooked seafood. However, there are also many Vibrio species which are potentially pathogenic to vertebrate and invertebrate aquatic animals, and of which little is known. In an attempt to develop rapid PCR detection methods for these latter class of vibrios, we have examined the 16S-23S intergenic spacers (IGSs) of 10 lesser-known Vibrio species and successfully developed species-specific primers for eight of them--Vibrio costicola, V. diazotrophicus, V. fluvialis, V. nigripulchritudo, V. proteolyticus, V. salmonicida, V. splendidus and V. tubiashii. The IGS amplicons were amplified using primers complementary to conserved regions of the 16S and 23S rRNA genes, and cloned into plasmid vectors and sequenced. Analysis of the IGS sequences showed that 37 ribosomal RNA (rrn) operons representing seven different IGS types have been cloned from the 10 vibrios. The three IGS types--IGS(0), IGS(IA) and IGS(Glu)--were the most prevalent forms detected. Multiple alignment of representative sequences of these three IGS types from different Vibrio species revealed several domains of high sequence variability, which were used to design species-specific primers for PCR. The specificity of the primers were evaluated using total DNA prepared from different Vibrio species and bacterial genera. The results showed that the PCR method can be used to reliably detect eight of the 10 Vibrio species in marine waters in this study. 相似文献
999.
V. I. Fel’dman L. V. Sazonova V. V. Milyavskii T. I. Borodina S. N. Sokolov A. Z. Zhuk 《Izvestiya Physics of the Solid Earth》2006,42(6):477-480
The shock metamorphism of schist consisting of garnet, biotite, quartz, and plagioclase is studied under shock wave loading of a sample in steel recovery ampoules of plane geometry. A maximum shock pressure was reached during several circulations of waves in the sample (stepwise shock compression) and varied within the range 19–52 GPa. The recovered samples were examined by the methods of scanning electron microscopy and microprobe and X-ray phase analysis. The results were compared with natural impactites and with shock-induced alterations in minerals loaded by a spherical convergent wave. It is established that, given a plane geometry of loading (stepwise shock compression), solid-state transformations at the lattice level (migration of chemical elements and formation of shock thermal aggregates) are not observed in all of the studied minerals, in contrast to natural impact processes and spherical geometry experiments. Under the conditions of our experiments, minerals melt at higher pressures than in the case of natural impact processes and spherical geometry experiments. However, for each mineral studied, the mechanical strain patterns at close shock pressures are, on the whole, the same for all of the aforementioned three variants of shock wave loading. 相似文献
1000.
P. Špaček Z. Sýkorová J. Pazdírková J. Švancara J. Havíř 《Studia Geophysica et Geodaetica》2006,50(2):233-258
The Variscan Bohemian Massif is disrupted by the NW-SE striking Elbe Fault System in its northern part. The increased tectonic
activity associated with this structure is manifested by increased seismicity in the eastern part of the Sudetes. With the
use of a temporary local seismic network, the total number of micro-earthquakes located in this region increased to 153 for
the period 1996–2003. The local magnitudes vary between −0.6 and 1.8 and the seismic energy was often released in swarm-like
sequences. Five seismic events with well-defined P-onset polarities at five or six stations enabled the estimation of focal
mechanisms. The present-day activity of the WNW-ESE to NNW-SSE fault systems is discussed on the basis of source mechanisms,
the alignment of the epicentres, as well as morphological and geological evidence. The majority of the recent seismic activity
is concentrated in a 40–60 km wide zone of a generally NW-SE trend. This structure represents a regional zone of weakness
within the SE termination of the Elbe Fault System, defined by a mesh of interconnected faults, of which many are deep-seated
and highly permeable and some are associated with light to moderate historical earthquakes. Both in the areas due south and
due north of this zone the present-day seismic activity is very low. The increased tectonic activity can be interpreted as
a result of the abundance of suitably oriented faults and their interconnection into major fault systems, the proximity of
the Outer Carpathian indentor and the Cainozoic volcanic and associated recent post-volcanic activity. The similar character
of swarms and their coincidence with the post-volcanic activity in the southeastern part of the Elbe Fault System and in some
focal zones of the western Bohemian seismically active area suggests that overpressurized fluids may represent a potential
swarm-triggering mechanism. 相似文献