Yash Aggarwal - Academia.edu (original) (raw)
Uploads
Papers by Yash Aggarwal
Journal of Geophysical Research, 1972
The principal purpose of this study is to report the existence of a zone of extremely low compres... more The principal purpose of this study is to report the existence of a zone of extremely low compressional-wave velocities in the uppermost mantle beneath most of the Lau basin, an interarc basin located west of or behind the Tonga Island arc. Velocities beneath the basin appear to be as low as 7.1 kin/sec. In contrast, times of P and S waves traveling beneath and parallel to the Tonga-Kermadec ridge indicate velocities of 8.45 and 4.75 km/sec, respectively. Although the lateral boundaries of the zone of low velocity beneath the Lau basin are not well defined, they coincide approximately with the boundaries of the zone of high seismic-wave attenuation existing beneath the Lau basin. The large difference (up to 15%) between P wave velocities beneath the Lau basin and those in areas adjacent to it probably requires partial melting in the upper mantle beneath the Lau basin. The P and $ velocities measured parallel and approximately perpendicular to the Tonga trench do not differ significantly and hence provide no evidence for anisotropy in the Pacific lithosphere. This paper reports a detailed study of lateral variations of P and $ wave velocities in the uppermost mantle beneath the Tonga-Fiji-Kermadec region of the southwest Pacific. ). High attenuation, or low Q, is often associated with low seismicwave velocities, and together they probably indicate anomalies in temperature or degree of partial melting in the mantle. Quantitative estimates of these thermal anomalies are more reliably determined from velocity data than from attenuation data, although observed effects of x Lamont-Doherty Geological Observatory contribution 1877. attenuation are the most prominent. This study confirms the correlation of low velocities with high attenuation for the Lau basin and thereby provides quantitative data for estimating physical properties of the anomalous zone.
This paper presents the results of an experimental investigation carried out to evaluate the shri... more This paper presents the results of an experimental investigation carried out to evaluate the shrinkage of High Strength Concrete. High Strength Concrete is made by partial replacement of cement by flyash and silica fume. The shrinkage of High Strength Concrete has been studied using the different types of coarse and fine aggregates i.e. Sandstone and Granite of 12.5 mm size
Journal of Geophysical Research, 1972
The principal purpose of this study is to report the existence of a zone of extremely low compres... more The principal purpose of this study is to report the existence of a zone of extremely low compressional-wave velocities in the uppermost mantle beneath most of the Lau basin, an interarc basin located west of or behind the Tonga Island arc. Velocities beneath the basin appear to be as low as 7.1 kin/sec. In contrast, times of P and S waves traveling beneath and parallel to the Tonga-Kermadec ridge indicate velocities of 8.45 and 4.75 km/sec, respectively. Although the lateral boundaries of the zone of low velocity beneath the Lau basin are not well defined, they coincide approximately with the boundaries of the zone of high seismic-wave attenuation existing beneath the Lau basin. The large difference (up to 15%) between P wave velocities beneath the Lau basin and those in areas adjacent to it probably requires partial melting in the upper mantle beneath the Lau basin. The P and $ velocities measured parallel and approximately perpendicular to the Tonga trench do not differ significantly and hence provide no evidence for anisotropy in the Pacific lithosphere. This paper reports a detailed study of lateral variations of P and $ wave velocities in the uppermost mantle beneath the Tonga-Fiji-Kermadec region of the southwest Pacific. ). High attenuation, or low Q, is often associated with low seismicwave velocities, and together they probably indicate anomalies in temperature or degree of partial melting in the mantle. Quantitative estimates of these thermal anomalies are more reliably determined from velocity data than from attenuation data, although observed effects of x Lamont-Doherty Geological Observatory contribution 1877. attenuation are the most prominent. This study confirms the correlation of low velocities with high attenuation for the Lau basin and thereby provides quantitative data for estimating physical properties of the anomalous zone.
This paper presents the results of an experimental investigation carried out to evaluate the shri... more This paper presents the results of an experimental investigation carried out to evaluate the shrinkage of High Strength Concrete. High Strength Concrete is made by partial replacement of cement by flyash and silica fume. The shrinkage of High Strength Concrete has been studied using the different types of coarse and fine aggregates i.e. Sandstone and Granite of 12.5 mm size