History of Boulder 1 at Station 2, Apollo 17 based on trace element interrelationships

Correlations among the trace and minor element pairs Cl and Br, Cl and P₂O₅, and Ru and Os, present in parent igneous rocks, generally survived the processes of boulder breccia formation. Fractions of the Cl, Br, and Hg that are mobilized by water leaching and/or volatilization at moderate temperatures (?450°C) place constraints on the thermal history of Boulder 1 and its component breccias. Since, and possibly during, consolidation, the boulder has probably not been subjected to temperatures of ?450°C. The parent rocks of the Apollo 17 boulder and breccia samples studied could have been derived from two initial magmas. Boulder 1, Station 2 gray competent breccias 72255 and 72275 Clast #2 appear to be genetically unrelated to gray competent breccia and anorthositic material 72215, or to light friable breccia 72275; they do appear to be related to samples 72395 (Boulder 2) and 76315 (Station 6 boulder). Vapor clouds from apparently external sources permeated the source regions of the boulders.     

Determination of total, commonality, and uniqueness of interpreted structural elements from remotely sensed data in Alaska

Statistical analysis is conducted to determine the unique value of real- and synthetic-aperture side-looking airborne radar (SLAR) to detect interpreted structural elements. SLAR images were compared to standard and digitally enhanced Landsat multispectral scanner (MSS) images and to aerial photographs. After interpretation of the imagery, data were cumulated by total length in miles and by frequency of counts. Maximum uniqueness is obtained first from real-aperture SLAR, 58.3% of total, and, second, from digitally enhanced Landsat MSS images, 54.1% of total.Publication authorized by the Director, U.S. Geological Survey, on 20 September 1984.     

A direction-sensitive underwater blast detector and its application for managing blast fishing

Little is known about the spatial and temporal distribution of blast fishing which hampers enforcement against this activity. We have demonstrated that a triangular array of hydrophones 1 m apart is capable of detecting blast events whilst effectively rejecting other sources of underwater noise such as snapping shrimp and nearby boat propellers. A total of 13 blasts were recorded in Sepangor bay, North of Kota Kinabalu, Sabah, Malaysia from 7th to 15th July 2002 at distances estimated to be up to 20 km, with a directional uncertainty of 0.2 degrees . With such precision, a network of similar hydrophone arrays has potential to locate individual blast events by triangulation to within 30 m at a range of 10 km.     

Solar rotation as measured in EUV chromospheric and coronal lines

Active regions were followed across the disk on OSO 4 spectroheliograms in the Lyman continuum (LC) and in Mg x 625. These observations indicate differential rotation with latitude, but not with height in the atmosphere. The measured equatorial sidereal rotation velocity is 14.7° ±0.2° per day in both chromospheric LC and coronal Mg x, where the quoted error is the standard deviation of a least-squares fit to the data.     

Air-Coupled Seismic Waves at Long Range from Apollo Launchings

Summary Microphones and seismographs were co-located in arrays on Skidaway Island, Georgia, for the launchings of Apollo 13 and 14, 374 km to the south. Simultaneous acoustic and seismic waves were recorded for both events at times appropriate to the arrival of the acoustic waves from the source. Significant comparisons of the true signals are (1) the acoustic signal is relatively broadband compared to the nearly monochromatic seismic signal; (2) the seismic signal is much more continuous than the more pulse-like acoustic signal; (3) ground loading from the pressure variations of the acoustic waves is shown to be too small to account for the seismic waves; (4) the measured phase velocities of both acoustic and seismic waves across the local instrument arrays differ by less than 6 per cent and possibly 3 per cent if experimental error is included. It is concluded that the seismic waves are generated by resonant coupling to the acoustic waves along some 10 km of path on Skidaway Island. The thickness of unconsolidated sediment on the island is appropriate to a resonant ground wave frequency of 3.5 to 4 Hz, as observed. Under appropriate conditions, ground wave observations may prove more effective means of detecting certain aspects of acoustic signals in view of the filtering of wind noise and amplification through resonance.     

The Resolving Power of Gross Earth Data

A gross Earth datum is a single measurable number describing some property of the whole Earth, such as mass, moment of interia, or the frequency of oscillation of some identified elastic-gravitational normal mode. We show how to determine whether a given finite set of gross Earth data can be used to specify an Earth structure uniquely except for fine-scale detail; and how to determine the shortest length scale which the given data can resolve at any particular depth. We apply the general theory to the linear problem of finding the depth-variation of a frequency-independent local Q from the observed quality factors Q of a finite number of normal modes. We also apply the theory to the non-linear problem of finding density vs depth from the total mass, moment, and normal-mode frequencies, in case the compressional and shear velocities are known.