Near-seismic effects in ULF fields and seismo-acoustic emission: statistics and explanation

International audiencePreseismic intensification of fracturing has been investigated from occurrence analysis of seismo-acoustic pulses (SA foreshocks) and ULF magnetic pulses (ULF foreshocks) observed in Karimshino station in addition to seismic foreshocks. Such analysis is produced for about 40 rather strong and nearby isolated earthquakes during 2 years of recording. It is found that occurrence rate of SA foreshocks increases in the interval (-12, 0 h) before main shock with 3-times exceeding of background level in the interval (-6, -3 h), and occurrence probability of SA foreshocks (pA~75%) is higher than probability of seismic foreshocks (ps~30%) in the same time interval.ULF foreshocks are masked by regular ULF activity at local morning and daytime, nevertheless we have discovered an essential ULF intensity increase in the interval (-3, +1 h) at the frequency range 0.05-0.3 Hz. Estimated occurrence probability of ULF foreshocks is about 40%. After theoretical consideration we conclude: 1) Taking into account the number rate of SA foreshocks, their amplitude and frequency range, they emit due to opening of fractures with size of L=70-200 m (M=1-2); 2) The electro-kinetic effect is the most promising mechanism of ULF foreshocks, but it is efficient only if two special conditions are fulfilled: a) origin of fractures near fluid-saturated places or liquid reservoirs (aquifers); b) appearance of open porosity or initiation of percolation instability; 3) Both SA and ULF magnetic field pulses are related to near-distant fractures (r<20-30 km); 4) Taking into account number rate and activation period of seismic, SA and ULF foreshocks, it is rather probable that opening of fractures and rupture of fluid reservoirs occur in the large preparation area with horizontal size about 100-200km

Electronic Orders Induced by Kondo Effect in Non-Kramers f-Electron Systems

This paper clarifies the microscopic nature of the staggered scalar order, which is specific to even number of f electrons per site. In such systems, crystalline electric field (CEF) can make a singlet ground state. As exchange interaction with conduction electrons increases, the CEF singlet at each site gives way to Kondo singlets. The collective Kondo singlets are identified with itinerant states that form energy bands. Near the boundary of itinerant and localized states, a new type of electronic order appears with staggered Kondo and CEF singlets. We present a phenomenological three-state model that qualitatively reproduces the characteristic phase diagram, which have been obtained numerically with use of the continuous-time quantum Monte Carlo combined with the dynamical mean-field theory. The scalar order observed in PrFe_4P_{12} is ascribed to this staggered order accompanying charge density wave (CDW) of conduction electrons. Accurate photoemission and tunneling spectroscopy should be able to probe sharp peaks below and above the Fermi level in the ordered phase.Comment: 7 pages, 8 figure

Microscopic Mechanism for Staggered Scalar Order in PrFe4P12

A microscopic model is proposed for the scalar order in PrFe4P12 where f2 crystalline electric field (CEF) singlet and triplet states interact with two conduction bands. By combining the dynamical mean-field theory and the continuous-time quantum Monte Carlo, we obtain an electronic order with staggered Kondo and CEF singlets with the total conduction number being unity per site. The ground state becomes semimetallic provided that the two conduction bands have different occupation numbers. This model naturally explains experimentally observed properties in the ordered phase of PrFe4P12 such as the scalar order parameter, temperature dependence of the resistivity, field-induced staggered moment, and inelastic features in neutron scattering. The Kondo effect plays an essential role for ordering, in strong contrast with ordinary magnetic orders by the RKKY interaction.Comment: 4 pages, 4figure

Electronic Order with Staggered Kondo and Crystalline Electric Field Singlets

Novel electronic order is found theoretically for a system where even number of localized electrons per site are coupled with conduction electrons. For precise quantitative study, a variant of the Kondo lattice model is taken with crystalline electric field (CEF) singlet and triplet states for each site. Using the dynamical mean-field theory combined with the continuous-time quantum Monte Carlo method, a staggered order with alternating Kondo and CEF singlets is identified for a case with one conduction electron per site being distributed in two conduction bands each of which is quarter-filled. This electronic order accompanies a charge density wave (CDW) of conduction electrons that accumulate more on Kondo-singlet sites than on CEF-singlet sites. Possible relevance of the present order to the scalar order in PrFe$_4$P$_{12}$ is discussed.Comment: 11 pages, 17 figure

Geophysical Observatory in Kamchatka region for monitoring of phenomena connected with seismic activity

Regular monitoring of some geophysical parameters in association with seismicity has been carried out since last year at the Japan-Russian Complex Geophysical Observatory in the Kamchatka region. This observatory was organized in connection with the ISTC project in Russia and was motivated by the results of the FRONTIER/RIKEN and FRONTIER/NASDA research projects in Japan. The main purpose of the observations is to investigate the electromagnetic and acoustic phenomena induced by the lithosphere processes (especially by seismic activity). The seismicity of the Kamchatka area is analyzed and a description of the observatory equipment is presented. At present, the activity of the observatory includes the seismic (frequency range &#x2206;F = 0.5 – 40 Hz) and meteorological recordings, together with seismo-acoustic (&#x2206;F = 30 – 1000 Hz) and electromagnetic observations: three-component magnetic ULF variations ( &#x2206;F = 0.003 – 30 Hz), three-component electric potential variations ( &#x2206;F <u><</u> 1.0 Hz), and VLF transmitter’s signal perturbations ( &#x2206;F ~ 10 – 40 kHz)

Study of electromagnetic emissions associated with seismic activity in Kamchatka region

International audienceA review of data processing of electromagnetic emission observation collected at the Complex Geophysical Observatory Karimshino (Kamchatka peninsula) during the first 5 months (July?November, 2000) of its operation is given. The main goal of this study addresses the detection of the phenomena associated with Kamchatka seismic activity. The following observations have been conducted at CGO: variations of ULF/ELF magnetic field, geoelectric potentials (telluric currents), and VLF signals from navigation radio transmitters. The methods of data processing of these observations are discussed. The examples of the first experimental results are presented

CP violation effect in long-baseline neutrino oscillation in the four-neutrino model

We investigate CP-violation effect in the long-baseline neutrino oscillation in the four-neutrino model with mass scheme of the two nearly degenerate pairs separated with the order of 1 eV, by using the data from the solar neutrino deficit, the atmospheric neutrino anomaly and the LSND experiments along with the other accelerator and reactor experiments. By use of the most general parametrization of the mixing matrix with six angles and six phases, we show that the genuine CP-violation effect could attain as large as 0.3 for $\Delta P(\nu_\mu\to\nu_\tau) \equiv P(\nu_\mu\to\nu_\tau) - P(\bar{\nu_\mu}\to\bar{\nu_\tau})$ and that the matter effect is negligibly small such as at most 0.01 for $\Delta P(\nu_\mu\to\nu_\tau)$ for $\Delta m^2 = (1-5)\times 10^{-3} {\rm eV}^2$, which is the mass-squared difference relevant to the long-baseline oscillation.Comment: 21 pages in LaTeX, 9 ps figures. Some changes in the Introduction and Reference

Naturalness Bounds on Dipole Moments from New Physics

Assuming naturalness that the quantum corrections to the mass should not exceed the order of the observed mass, we derive and apply model-independent bounds on the anomalous magnetic moments and electric dipole moments of leptons and quarks due to new physics.Comment: 4 pages, 2 figure

Pointing calibration of GroundBIRD telescope using Moon observation data

Understanding telescope pointing (i.e., line of sight) is important for observing the cosmic microwave background (CMB) and astronomical objects. The Moon is a candidate astronomical source for pointing calibration. Although the visible size of the Moon (\ang{;30}) is larger than that of the planets, we can frequently observe the Moon once a month with a high signal-to-noise ratio. We developed a method for performing pointing calibration using observational data from the Moon. We considered the tilts of the telescope axes as well as the encoder and collimation offsets for pointing calibration. In addition, we evaluated the effects of the nonuniformity of the brightness temperature of the Moon, which is a dominant systematic error. As a result, we successfully achieved a pointing accuracy of \ang{;3.3}. This is one order of magnitude smaller than an angular resolution of \ang{;36}. This level of accuracy competes with past achievements in other ground-based CMB experiments using observational data from the planets.Comment: 18 pages, 17 figures, 3 table