منابع مشابه
Time-Distance Sunspot Seismology with GONG Data1
We present time-distance analyses of several active regions and a region of quiet Sun observed with the Global Oscillation Network Group (GONG). Analyzing temporal correlations between the p-mode oscillation signal observed within the sunspots with the signals integrated within surrounding annuli, we connrm the recent nding of Duvall and his colleagues that travel times (+) for outward propagat...
متن کاملSeparating Surface Magnetic Effects in Sunspot Seismology: New Time-distance Helioseismic Diagnostics
Time-distance helioseismic measurements in surfaceand deep-focus geometries for wave-paths that distinguish surface magnetic contributions from those due to deeper perturbations beneath a large sunspot are presented and analysed. Travel times showing an increased wave speed region extending down to about 18 Mm beneath the spot are detected in deep-focus geometry that largely avoids use of wave ...
متن کاملRadiative transfer effects on Doppler measurements as sources of surface effects in sunspot seismology
We show that the use of Doppler shifts of Zeeman sensitive spectral lines to observe waves in sunspots is subject to measurement specific phase shifts arising from, (i) altered height range of spectral line formation and the propagating character of p mode waves in penumbrae, and (ii) Zeeman broadening and splitting. We also show that these phase shifts depend on wave frequencies, strengths and...
متن کاملGPS seismology
GPS seismology uses convential geodetic models to analyze GPS data at high sampling rates, such as 1 Hz. GPS seismology results are shown for the Denali, San Simeon, Tokachi-oki, and Chuetsu earthquakes. Records for these earthquakes indicate that GPS is an excellent instrument for measuring large displacements near earthquake ruptures. GPS systems can be improved for seismic applications if th...
متن کاملStatistical Seismology
Stochastic models with an increasing component of physical reasoning have been slowly gaining acceptance over the last two decades. The subject of statistical seismology aims to bridge the gap between physics-based models without statistics, and statistics-based models without physics. This volume, which is based largely on papers presented at the 3rd International Workshop on Statistical Seism...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1988
ISSN: 0074-1809
DOI: 10.1017/s0074180900158024