On the relationships of water-level variations in the E-1 well, Kamchatka to the 2008–2009 resumption of activity on Koryakskii volcano and to large (M ≥ 5) earthquakes

We discuss the water-level variations in the E-1 well for the time period between May 2006 and 2010, inclusive. A trend towards an increasing level at an abnormally high rate occurred from mid-2006 to December 2009. This increase is regarded as the response of the aquifer of gas-saturated ground water that exists in the volcanogenic-sedimentary deposits of the Avacha volcano-tectonic depression to volumetric compression strain changes during the precursory period and the occurrence of a swarm of small earthquakes $\left( {K_{S_{\max } } = 8.3} \right)$ in the area of Koryakskii Volcano and to its phreatic eruption. We estimated the volumetric compression as ??? = ?(4.1 × 10^?6?1.5 × 10^?5) from the amplitude of water-level rise using the elastic parameters of the water-saturated rocks. While the strain source was active, we observed a decreasing sensitivity of the hydrodynamic regime in the well to the precursory processes before large (M ?? 5.0) tectonic earthquakes.     

The possibility of estimating the coseismic deformation from water level observations in wells

A method for point estimation of coseismic volume deformation from amplitudes of earthquake-induced jumps in the water level and from the tidal sensitivity of the water level is presented. Application of this method is illustrated by six Kamchatka earthquakes of 1997–2004 with M _w = 6.2–7.8 that occurred 128–316 km from the YuZ-5 well. Estimates of coseismic deformation provided by the level gage observations and by the model agree in amplitude and sign. The model reproduces an extended dislocation source in a homogeneous elastic isotropic half-space. Source rupture parameters correspond to focal mechanisms from the CMT international catalog. Consistence in experimental and theoretical estimates of the volume coseismic deformation indicates the high strain-resistance properties of YuZ-5 borehole and the possibility of quantitative estimation of seismotectonic deformation from high-precision water level measurements with time resolution not lower than 10 minutes.     

Intermediate-term precursors of large (<Emphasis Type="Italic">M</Emphasis> ≥ 6.6) Kamchatka earthquakes for the period from 1987 to 2004: A retrospective assessment of their information content for prediction

Data from the literature were used to systematize intermediate-term (with advance times of 1 month to ∼2.5 years) precursors to the M ≥ 6.6 Kamchatka earthquakes of 1987–2004. The precursors were observed as changes in seismological, geodetic, geophysical, water-level, and hydrochemical parameters. Retrospective assessment of the information content in these intermediate-term precursors for earthquake prediction is in progress. The focus was on estimating the occurrence times of various precursors as functions of earthquake parameters (magnitude M, hypocentral distance R, and epicenter location). In the conditions of the Kamchatka observing network, precursors can be identified by a combination of methods, mostly before M ∼ 7 earthquakes or greater south of the Kronotskii Peninsula, for which M/logR ≥ 3. It is shown that the relative proportion of earthquakes for which precursors have been identified in the observations considered here is 0.43–0.86.     

Peculiar motions in the region of the Ursa Major supercluster of galaxies

We have investigated the peculiar motions of clusters of galaxies in the Ursa Major (UMa) supercluster and its neighborhood. Based on SDSS (Sloan Digital Sky Survey) data, we have compiled a sample of early-type galaxies and used their fundamental plane to determine the cluster distances and peculiar velocities. The samples of early-type galaxies in the central regions (within R ₂₀₀) of 12 UMa clusters of galaxies, in three main subsystems of the supercluster—the filamentary structures connecting the clusters, and in nine clusters from the nearest UMa neighborhood have similar parameters. The fairly high overdensity (3 by the galaxy number and 15 by the cluster number) suggests that the supercluster as a whole is gravitationally bound, while no significant peculiar motions have been found: the peculiar velocities do not exceed the measurement errors by more than a factor of 1.5–2. The mean random peculiar velocities of clusters and the systematic deviations from the overall Hubble expansion in the supercluster are consistent with theoretical estimates. For the possible approach of the three UMa subsystems to be confirmed, the measurement accuracy must be increased by a factor of 2–3.     

Diagnostics of a flare on EQ Peg B from optical pulsations

Based on the methods of coronal seismology, we have investigated the ten-second quasi-periodic pulsations of the optical flare emission from the active red dwarf EQ Peg B detected with the William Herschel Telescope on La Palma. We propose and analyze a model in which they could be produced by sausage oscillations of a coronal flare loop. The amplitude and phase relations between the displacement components of the radial oscillations and the conditions for their excitation in loops with footpoints frozen into the photosphere are considered. The temperature (≈6 × 10⁷ K), plasma density (≈2.7 × 10¹¹ cm⁻³), and magnetic field strength (≈540 G) in the region of energy release have been determined. Our estimate of the flare loop length (≈0.4R _⋆) provides evidence for the existence of extended coronae on red dwarf stars.     

Enigmatic diamonds in Archean calc-alkaline lamprophyres of Wawa, southern Ontario, Canada

A suite of 80 macrodiamonds recovered from volcaniclastic breccia of Wawa (southern Ontario) was characterized on the basis of morphology, nitrogen content and aggregation, cathodoluminescence (CL), and mineral inclusions. The host calc-alkaline lamprophyric breccias were emplaced at 2.68–2.74 Ga, contemporaneously with voluminous bimodal volcanism of the Michipicoten greenstone belt. The studied suite of diamonds differs from the vast majority of diamond suites found worldwide. First, the suite is hosted by calc-alkaline lamprophyric volcanics rather than by kimberlite or lamproite. Second, the host volcanic rock is amongst the oldest known diamondiferous rocks on Earth, and has experienced regional metamorphism and deformation. Finally, most diamonds show yellow-orange-red CL and contain mineral inclusions not in equilibrium with each other or their host diamond. The majority of the diamonds in the Wawa suite are colorless, weakly resorbed, octahedral single crystals and aggregates. The diamonds contain 0–740 ppm N and show two modes of N aggregation at 0–30 and 60–95% B-centers suggesting mantle storage at 1,100–1,170°C. Cathodoluminescence and FTIR spectroscopy shows that emission peaks present in orange CL stones do not likely result from irradiation or single substitutional N, in contrast to other diamonds with red CL. The diamonds contain primary inclusions of olivine (Fo₉₂ and Fo₈₉), omphacite, orthopyroxene (En₉₃), pentlandite, albite, and An-rich plagioclase. These peridotitic and eclogitic minerals are commonly found within single diamonds in a mixed paragenesis which also combines shallow and deep phases. This apparent disequilibrium can be explained by effective small-scale mixing of subducted oceanic crust and mantle rocks in fast “cold” plumes ascending from the top of the slabs in convergent margins. Alternatively, the diamonds could have formed in the pre-2.7–2.9 Ga cratonic mantle and experienced subsequent alteration of syngenetic inclusions related to host magmatism and ensuing metamorphism. Neither orogenic nor cratonic model of the diamond origin fully explains all of the observed characteristics of the diamonds and their host rocks. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.