Broadband Records of Earthquakes in Deep Gold Mines and a Comparison with Results from SAFOD, California

For one week during September 2007, we deployed a temporary network of field recorders and accelerometers at four sites within two deep, seismically active mines. The ground-motion data, recorded at 200 samples/sec, are well suited to determining source and ground-motion parameters for the mining-induced earthquakes within and adjacent to our network. Four earthquakes with magnitudes close to 2 were recorded with high signal/noise at all four sites. Analysis of seismic moments and peak velocities, in conjunction with the results of laboratory stick-slip friction experiments, were used to estimate source processes that are key to understanding source physics and to assessing underground seismic hazard. The maximum displacements on the rupture surfaces can be estimated from the parameter Rv, where v is the peak ground velocity at a given recording site, and R is the hypocentral distance. For each earthquake, the maximum slip and seismic moment can be combined with results from laboratory friction experiments to estimate the maximum slip rate within the rupture zone. Analysis of the four M 2 earthquakes recorded during our deployment and one of special interest recorded by the in-mine seismic network in 2004 revealed maximum slips ranging from 4 to 27 mm and maximum slip rates from 1.1 to 6:3 m=sec. Applying the same analyses to an M 2.1 earthquake within a cluster of repeating earthquakes near the San Andreas Fault Observatory at Depth site, California, yielded similar results for maximum slip and slip rate, 14 mm and 4:0 m=sec

Temperature-Dependent X-Ray Absorption Spectroscopy of Colossal Magnetoresistive Perovskites

The temperature dependence of the O K-edge pre-edge structure in the x-ray absorption spectra of the perovskites La(1-x)A(x)MnO(3), (A = Ca, Sr; x = 0.3, 0.4) reveals a correlation between the disappearance of the splitting in the pre-edge region and the presence of Jahn-Teller distortions. The different magnitudes of the distortions for different compounds is proposed to explain some dissimilarity in the line shape of the spectra taken above the Curie temperature.Comment: To appear in Phys. Rev. B, 5 pages, 3 figure

(Un)Fair(ly) Unknown: New and Neglected Arthurian Television Programming

(Un)Fair(ly) Unknown: New and Neglected Arthurian Television Programming Panel by Carl B. Sell, Richard Fahey, Michael Torregrossa, and Rachael K. Warmington Tech Mod: Tim Len

Ion-lithium collision dynamics studied with an in-ring MOTReMi

We present a novel experimental tool allowing for kinematically complete studies of break-up processes of laser-cooled atoms. This apparatus, the 'MOTReMi', is a combination of a magneto-optical trap (MOT) and a Reaction Microscope (ReMi). Operated in an ion-storage ring, the new setup enables to study the dynamics in swift ion-atom collisions on an unprecedented level of precision and detail. In first experiments on collisions with 1.5 MeV/amu O$^{8+}$-Li the pure ionization of the valence electron as well as ionization-excitation of the lithium target has been investigated

Keramikken og ovnen fra Hellum samt en beskrivelse af brændingsforløbet

The pottery and kiln from Hellum and a discription of the firing By Annette B. Bibby & Inge Sell Duplicating the Hellum kiln consists of reconstructing both the kiln itself and the pottery vessels to be fired in it. The original vessels are all spherical pots of different sizes, produced without a fast wheel and unglazed. The reconstructed pots are therefore built in the lap, and when the clay is sufficiently stable the outer surface is clapped with a clapping bat. After finishing the rim by bending it out over the righthand thumb, the pots are left to dry completely before being fired in the kiln. The kiln consists of an underground firing chamber with a narrow stoking channel and a firing chamber above ground. To build the floor of the firing chamber a large stone was placed in the middle of the firing chamber, with thick clay bars spreading out to the outer walls. For the reconstruction of the kiln the building site is dug and the floor and outer walls of the firing chamber are moulded in clay. The large stone is placed in the middle and covered with clay. Then the difficult task of building the floor of the firing chamber begins. Thick bars of clay are arched between the stone and the outer walls. The finished floor looks like a wheel with thick spokes. Finally the walls of the firing chamber are moulded, narrowing upward and leaving an outlet for smoke. Stacking produces a problem, because some of the pots have to hang, firmly wedged by those standing on the bars, over the holes down to the firing chamber. Taking great care in placing the pots solves this problem, and the rest of the stacking is easily done. The firing starts very slowly with a small fire in the stoking channel. After two hours with moderate feeding, the fire is allowed to burn more freely and wood fuel and embers are pushed into the fire chamber. A problem with steam in the outlet smoke from very wet fuel forces us to keep the outlet open for longer than planned, but after five hours’ firing it is narrowed to ten by ten centimetres. After a further five hours’ of firing the temperature reaches 820 degrees Celsius, and a glance down into the kiln shows the pots glowing a translucent red. Thereafter the kiln is closed