Visual and infrared observations of wind streaks on Mars

Estimation of surface properties and physical setting of three common Martian wind streak types (bright, dark, and splotch related) provides constraints on models of the formation and variability of streaks. Bright streaks form independently of surface properties other than local topography. This is consistent with their formation being due to deposition of atmospheric dust in the lee of topographic features. Although they are widespread on Mars, dark streaks are noted as variable only in regions near 30°S latitude and elevations between 3 and 7 km, and are associated with dark surfaces that have relatively high thermal inertias. Splotch-related streaks occur at elevations between 0 and 6 km and in regions of relatively high thermal inertia. Splotch-related streaks occur near the boundaries of thermally defined regions, such as the south polar cap and other areas of either low or high thermal inertia. These thermal conditions are responsible for the production of surface winds which form and modify these streaks. The source of sidements which form splotch-related streaks varies from dunes to well-indurated stratified deposits. Regional studies of the various types in Syrtis Major, Syria Planum-Claritas Fossae, Oxia Palus, Mesogea, and Pettit craters and Noachis confirm that the correlations found at the global level occur at regional scales.     

Measurements of solar magnetic fields by Fourier transform techniques

If the basic profile shapes of the normal Zeeman triplet do not have zeros in their Fourier transform, the magnetic field splitting can be determined independent of the profile shape. When the ratio of the splitting of the components is greater than the intrinsic FWHM of the component profiles the magnetic splitting can be determined with significantly greater accuracy than the measurement accuracy of the original profile. For Gaussian shaped components and a ratio of magnetic splitting to FWHM of 1.5 the noise reduction factor is 25.     

AQD occurrence at Addis Ababa,Trivandrum and Alibag

The effect of the equatorial electrojet is sufficient to reduce the probability of an abnormal quiet day occurring at Addis Ababa, Trivandrum and Alibag. Addis Ababa AQD occurrence exhibits an anomalous or subdued relationship to solar intensity, compared to that of Alibag, Trivandrum, and Greenwich/Abinger/Hartland; this is thought to be due to some unknown characteristic of the PM electrojet. Few AQD's are common to Addis Ababa and Trivandrum, Addis Ababa and Alibag, and Trivandrum and Alibag compared to the number common to Abinger and Wingst.     

Flexible multimethod approach for seismic site characterization

Journal of Seismology - We describe the flexible multimethod seismic site characterization technique for obtaining shear-wave velocity (VS) profiles and derivative information, such as the...     

Introduction to the special issue of the Consortium of Organizations for Strong Motion Observation Systems (COSMOS) international guidelines for applying noninvasive geophysical techniques to characterize seismic site conditions

Journal of Seismology -     

A review of near-surface QS estimation methods using active and passive sources

Journal of Seismology - Seismic attenuation and the associated quality factor (Q) have long been studied in various sub-disciplines of seismology, ranging from observational and engineering...     

Calibration for the shear strain of 3-component borehole strainmeters in eastern Taiwan through Earth and ocean tidal waveform modeling

We propose an approach for calibrating the horizontal tidal shear components [(differential extension (\(\gamma _1\)) and engineering shear (\(\gamma _2\))] of two Sacks–Evertson (in Pap Meteorol Geophys 22:195–208, 1971) SES-3 borehole strainmeters installed in the Longitudinal Valley in eastern Taiwan. The method is based on the waveform reconstruction of the Earth and ocean tidal shear signals through linear regressions on strain gauge signals, with variable sensor azimuth. This method allows us to derive the orientation of the sensor without any initial constraints and to calibrate the shear strain components \(\gamma _1\) and \(\gamma _2\) against \(M_2\) tidal constituent. The results illustrate the potential of tensor strainmeters for recording horizontal tidal shear strain.