On induction effects at EISCAT and IMAGE magnetometer stations     

Ari Viljanen  Kirsti Kauristie  Kari Pajunpää 《Geophysical Journal International》1995,121(3):893-906

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Radiation of elastic waves from sources embedded in anisotropic inclusions     

Ari Ben-Menahem  Richard L. Gibson Jr 《Geophysical Journal International》1995,122(1):249-265

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Modelling of space weather effects on pipelines   总被引：1，自引：0，他引：1  

Antti Pulkkinen  Risto Pirjola  David Boteler  Ari Viljanen  Igor Yegorov   《Journal of Applied Geophysics》2001,48(4)

The interaction between the solar wind and the Earth's magnetic field produces time varying currents in the ionosphere and magnetosphere. The currents cause variations of the geomagnetic field at the surface of the earth and induce an electric field which drives currents in oil and gas pipelines and other long conductors. Geomagnetically induced currents (GIC) interfere with electrical surveys of pipelines and possibly contribute to pipeline corrosion.In this paper, we introduce a general method which can be used to determine voltage and current profiles for buried pipelines, when the external geoelectric field and the geometry and electromagnetic properties of the pipeline are known. The method is based on the analogy between pipelines and transmission lines, which makes it possible to use the distributed source transmission line (DSTL) theory. The general equations derived for the current and voltage profiles are applied in special cases. A particular attention is paid to the Finnish natural gas pipeline network.This paper, related to a project about GIC in the Finnish pipeline, thus provides a tool for understanding space weather effects on pipelines. Combined with methods of calculating the geoelectric field during magnetic storms, the results are applicable to forecasting of geomagnetically induced currents and voltages on pipelines in the future.  相似文献   

A method for determination of epicenters of near earthquakes     

Mr. Ari Ben-Menahem M. Sc.  Dr. Markus Båth 《Pure and Applied Geophysics》1960,46(1):37-46

Summary A method is developed, which permits a rapid and reliable determination of the location of near epicenters (within about 10^o) using the differences of arrival times of a common phase (usually Sg) to a net of three stations. The resulting equation for computation of epicentral distances is solved numerically once for all by an electronic computer for every station triangle and for all possible time differences for every wave used. The calculated epicentral distances and coordinates are arranged in tables with the two travel-time differences for each triangle as entries. Such tables permit an immediate solution of the problem in every special case. The accuracy of the method is investigated, and necessary precautions in its use are emphasized. Application is made to a few cases of Sg recorded at the Swedish stations.

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Zusammenfassung Eine Methode wird entwickelt, die eine schnelle und zuverlässige Bestimmung der Lage von nahegelegenen Epizentren (innerhalb rund 10^o) mittels der Laufzeitdifferenzen einer gegebenen Welle (gewöhnlichSg) in einem Netz von drei Stationen ermöglicht. Die erhaltene Gleichung für die Berechnung der Herdentfernungen wird mittels einer elektronischen Rechenmaschine für jedes Stations-dreieck und für alle möglichen Zeitdifferenzen für jede verwendete Welle ein für allemal numerisch gelöst. Die berechneten Herdentfernungen und-Koordinaten werden in Tabellenform dargestellt mit den beiden Laufzeitdifferenzen für jedes Dreieck als Eingangswerte. Solche Tabellen ermöglichen eine unmittelbare Lösung des Problems in jedem einzelnen Fall. Die Genauigkeit der Methode wird untersucht, und die notwendigen Vorsichtsmassregeln bei ihrer Verwendung werden hervorgehoben. Die Methode wird auf einige Registrierungen vonSg an den schwedischen Stationen angewendet.

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Eigenvibrations of the Earth Excited by Finite Dislocations–I Toroidal Oscillations     

Sarva Jit Singh  Ari Ben-Menahem 《Geophysical Journal International》1969,17(2):151-177

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Variation of slip and creep along the levant rift over the past 4500 years     

Ari Ben-Menahem 《Tectonophysics》1981,80(1-4):183-197

Frequency—magnitude relations were established for a fault system embedded in a shear zone with dimensions 1000 km × 200 km that extends from the Gulf of Elat to the East-Anatolian fault. The resulting frequency—magnitude relations were found to be in good agreement with both the documented instrumental earthquake statistics for M_L 4.5 in the present century and microearthquake activity for M_L 1.5 recorded in Israel and some adjacent territories during 1976–1979. When these frequency—magnitude relations are extended to 2500 B.C., one can account for the maximal magnitude earthquakes that echo in the Bible and are manifested in archaeological excavations.

It is found that seismic slip-rates increase significantly from south toward north in such a way that in north-central Israel and Lebanon, seismic slip constitutes only 1/3 of the motion, the rest being attributed to visco-elastic processes. Further north, as one approaches the collision zone with the Turkish plate, aseismicity tends to disappear and the slip is purely seismic.  相似文献   

Renormalization of the magnitude scale     

Ari Ben-Menahem 《Physics of the Earth and Planetary Interiors》1977,15(4):315-340

Seismic source parameters of 27 earthquakes in the magnitude range 7.0–8.5 that occurred during 1906–1969 and that were determined mostly from inversion of long-period seismic surface waves in the period range 100–200 s are re-examined. Among these are five re-evaluations (Chile, May 1960; Sanriku, March 1933; Assam, August 1950; Alaska, July 1958; Alaska, March 1964) and six new analyses (Aleutian Ils., March 1957; Peru, Nov. 1947; New Guinea, Feb. 1938; Queen Charlotte Ils., August 1949; San Francisco, April 1906; Kern County, July 1952).It is shown both theoretically and experimentally that the strong azimuthal dependence of the far displacement field makes the 20-s magnitude vulnerable to uncertainties up to $\text{2}\text{3}$ unit of magnitude. These uncertainties are inherent in the magnitude definition, depend on the azimuth of the observer and are unremovable.A remedy is offered in the form of a new magnitude scale, based on the cube root of the potency (product of fault area S and average slip $\text{U}$). In the magnitude range 6.75–8.5 this scale is centigrade. It is shown that $\text{(}\text{U}\text{S)}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}$ is the “azimuth-free” part of the Richter magnitude and its adoption as a basis for a new magnitude scale may rid observations of azimuthal ambiguities.  相似文献   

Holocene rockfalls in the southern Negev Desert,Israel and their relation to Dead Sea fault earthquakes     

Yair Rinat  Ari Matmon  Maurice Arnold  Georges Aumaître  Didier Bourlès  Karim Keddadouche  Naomi Porat  Efrat Morin  Robert C. Finkel 《Quaternary Research》2014

Rockfall ages in tectonically active regions provide information regarding frequency and magnitude of earthquakes. In the hyper-arid environment of the Dead Sea fault (DSF), southern Israel, rockfalls are most probably triggered by earthquakes. We dated rockfalls along the western margin of the DSF using terrestrial cosmogenic nuclides (TCN). At each rockfall site, samples were collected from simultaneously exposed conjugate boulders and cliff surfaces. Such conjugate samples initially had identical pre-fall (“inherited”) TCN concentrations. After boulder detachment, these surfaces were dosed by different production rates due to differences in post-fall shielding and geometry. However, in our study area, pre-rockfall inheritance and post-rockfall production rates of TCN cannot be evaluated. Therefore, we developed a numerical approach and demonstrated a way to overcome the above-mentioned problems. This approach can be applied in other settings where rockfalls cannot be dated by simple exposure dating. Results suggest rockfall ages between 3.6 ± 0.8 and 4.7 ± 0.7 ka. OSL ages of sediment accumulated behind the boulders range between 0.6 ± 0.1 and 3.4 ± 1.4 ka and support the TCN results. Our ages agree with dated earthquakes determined in paleoseismic studies along the entire length of the DSF and support the observation of intensive earthquake activity around 4–5 ka.  相似文献   

Galactosynthesis: halo histories, star formation and discs     

Ari Buchalter  Raul Jimenez  Marc Kamionkowski 《Monthly notices of the Royal Astronomical Society》2001,322(1):43-66

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Application of conformal mapping to 2-D conductivity structures with non-uniform primary sources     

Pekka Janhunen  Ari Viljanen 《Geophysical Journal International》1991,105(1):185-190

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