(Table 2) Picked maximum velocities from 3 radars (RAY, SHK, and SUM), showing 10 explosions at Erebus volcano, Antarctica, and their respective directivity vectors

We used a novel system of three continuous wave Doppler radars to successfully record the directivity of i) Strombolian explosions from the active lava lake of Erebus volcano, Antarctica, ii) eruptions at Stromboli volcano, Italy, and iii) a man-made explosion in a quarry. Erebus volcano contains a convecting phonolite lava lake, presumably connected to a magma chamber at depth. It is one of the few open vent volcanoes that allow a direct observation of source processes during explosions. Its lava lake is the source of frequent violent Strombolian explosions, caused by large gas bubbles bursting at the lake surface. The exact mechanism of these bubble bursts is unclear, as is the mechanism of the creation of the infrasound signal accompanying the explosions. We use the Doppler radar data to calculate the directivity of Strombolian eruptions at Erebus. This allows us to derive information about the expected type of infrasound source pattern (i.e. the role of a dipole in addition to the monopole signature) and the physical structure of the volcano. We recorded 10 large explosions simultaneously with three radars, enabling us to calculate time series of 3D directivity vectors (i.e. effectively 4D), which describe the direction of preferred expansion of the gas bubble during an explosion. Such directivity information allows a comparison to dipole infrasound radiation patterns recorded during similar explosions only a few weeks later. Video observations of explosions support our interpretation of the measurements. We conclude that at Erebus, the directivity of explosions is mainly controlled by random processes. Since the geometry of the uppermost conduit is assumed to have a large effect on the directivity of explosions, the results suggest a largely symmetrical uppermost conduit with a vertical axis of symmetry. For infrasound recordings, a significant dipole signature can be expected in addition to the predominant monopole signature.

Geochemistry of nodules from a young seamount

Manganese nodules made of radiating rods of well crystallized birnessite were sampled at 8 degree 481.2'N, 103 degree 53.8W, 1875 m below sea level by a dredge that also collected hyaloclastite and basaltic talus. The nodule field is on the floor of a caldera within a young tholeiitic seamount and was discovered and photographed during a deep-two survey. It is interpreted as a brecciated hydrothermal deposit, crystallized from an amorphous manganese oxide precipitate that formed when seawater-based hydrothermal fluids mixed with oxidized seawater. The nodules and surrounding igneous rocks have subsequently been encrusted with hydrogenous ferromanganese oxides.

Radiofrequency radiation levels and population exposure in urban areas of the Eastern United States /

Issued May 1978.

Manual of protective action guides and protective actions for nuclear incidents.

"EPA 520/1-75-001-A"--Cover.

Course manual for X-ray measurements (GS-462).

Mode of access: Internet.

Evaluation of occupational hazards from industrial radiation : a survey of selected states /

"NIOSH technical information."

Factors affecting the use of CaF2 : Mn thermoluminescent dosimeters for low-level environmental radiation monitoring /

Mode of access: Internet.

Leakage in the proximity of microwave diathermy applications used on humans or phantom models /

Mode of access: Internet.

The ORINS human radiation counters : a preliminary report /

"July 1960."

Final off-site report of the Project Sedan event July 6, 1962 : Plowshare Program /

Prepared for the U.S. Atomic Energy Commission.

Radiation application and fission product utilization : a bibliography of selected unclassified literature /

"Office of Isotopes Development, U.S. Atomic Energy Commission."

Le droit de la guerre et de la paix /

Mode of access: Internet.