Distance Education in Engineering for Developing Countries

Teaching/Communication/Extension/Profession,

Surface deformation and elasticity studies in the Virgin Islands

The report consists of four sections. The first section describes tilt and leveling measurements on Anegada, the most northerly of the British Virgin Islands; the second section contains a discussion of sea-level measurements that were initiated in the region and which played a significant role in the development of a network of sea-level monitors now telemetered via satellite from the Alaskan Shumagin Islands. The third part of the report is a brief description of surface deformation measurements in Iceland using equipment and techniques developed by the subject grant. The final part of the report describes the predicted effects of block surface fragmentation in tectonic areas on the measurement of tilt and strain

[Activities of Dept. of Geological Sciences, Colorado University]

Using remotely sensed data and GPS observations we completed a study of neotectonic processes responsible for landscape changes in an area of active extensional deformation and volcanism. The findings from this study describe the extensional processes operating in the region of the Afar triple junction and the northern Ethiopian rift

Gravity and the geoid in the Nepal Himalaya

Materials within the Himalaya are rising due to convergence between India and Asia. If the rate of erosion is comparable to the rate of uplift, the mean surface elevation will remain constant. Any slight imbalance in these two processes will lead to growth or attrition of the Himalaya. Although buried rocks, minerals and surface control points in the Himalaya are undoubtably rising, the growth or collapse or the Himalaya depends on the erosion rate which is invisible to geodetic measurements. A way to measure erosion rate is to measure the rate of change of gravity in a region of uplift. Essentially gravity should change precisely in accord with a change in elevation of the point in a free air gradient if erosion equals uplift rate. A measurement of absolute gravity was made simultaneously with measurements of GPS height within the Himalaya. Absolute gravity is estimated from the change in velocity per unit distance of a falling corner cube in a vacuum. Time is measured with an atomic clock and the unit distance corresponds to the wavelength of an iodine stabilized laser. An experiment undertaken in the Himalaya in 1991 provide a site description also with a instrument description

A More General Quantum Searching Algorithm And the Precise Formula of the Amplitude and the Non-symmetric Effects of Different Rotating Angles

This paper presented two general quantum search algorithms. We derived the iterated formulas and the simpler approximate formulas and the precise formula for the amplitude in the desired state. A mathematical proof of Grover's algorithm being optimal among the algorithms with arbitrary phase rotations was given in this paper. This first reported the non-symmetric effects of different rotating angles, and gave the first-order approximate phase condition when rotating angles are different.Comment: 13 pages, misusing tex formatting commands in title, shorted the titles, corrected typos, added the justifications to the section

Geodetic contributions to the study of seismotectonics in India

Earthquakes in India are caused by the release of elastic strain energy created and replenished by the stresses resulting from India's collision with Asia. Accumulating strain distorts the surface of the Indian plate, which despite its slow development can now be detected using precision geodesy. The largest and most severe earthquakes occur on the boundaries of the Indian plate to the east, north and west of the subcontinent. Historically, these areas have been somewhat neglected by precise geodesy and it is only recently that suitably dense networks capable of spanning entire plate boundaries have been developed. Earthquakes within the subcontinent, though devastating, have also remained unserved by historical geodesy in India because the rupture areas of these events are small and have tended to occur between networks of adequate precision. Since 1990, the widespread availability of GPS geodesy has resulted in a number of significant findings related to the translation, deformation and rotation of the Indian plate, and to deformation of its margins. The next decade is likely to see the uncertainties of these estimates fall by a factor of 4, permitting estimates of changes of rate in space and time. We discuss these new findings and their historical antecedents, and identify current trends in seismogeodetic research that are likely to contribute to a new understanding of future Indian earthquakes

Intensity, Magnitude, Location, and Attenuation in India for Felt Earthquakes since 1762

A comprehensive, consistently interpreted new catalog of felt intensities for India (Martin and Szeliga, 2010, this issue) includes intensities for 570 earthquakes; instrumental magnitudes and locations are available for 100 of these events. We use the intensity values for 29 of the instrumentally recorded events to develop new intensity versus attenuation relations for the Indian subcontinent and the Himalayan region. We then use these relations to determine the locations and magnitudes of 234 historical events, using the method of Bakun and Wentworth (1997). For the remaining 336 events, intensity distributions are too sparse to determine magnitude or location. We evaluate magnitude and location accuracy of newly located events by comparing the instrumental- with the intensity-derived location for 29 calibration events, for which more than 15 intensity observations are available. With few exceptions, most intensity-derived locations lie within a fault length of the instrumentally determined location. For events in which the azimuthal distribution of intensities is limited, we conclude that the formal error bounds from the regression of Bakun and Wentworth (1997) do not reflect the true uncertainties.We also find that the regression underestimates the uncertainties of the location and magnitude of the 1819 Allah Bund earthquake, for which a location has been inferred from mapped surface deformation. Comparing our inferred attenuation relations to those developed for other regions, we find that attenuation for Himalayan events is comparable to intensity attenuation in California (Bakun and Wentworth, 1997), while intensity attenuation for cratonic events is higher than intensity attenuation reported for central/eastern North America (Bakun et al., 2003). Further, we present evidence that intensities of intraplate earthquakes have a nonlinear dependence on magnitude such that attenuation relations based largely on small-to-moderate earthquakes may significantly overestimate the magnitudes of historical earthquakes

Seismic slip deficit in the Kashmir Himalaya from GPS observations

GPS measurements in Kashmir Himalaya reveal rangenormal convergence of 11±1 mm/yr with dextral shear of 5±1 mm/yr. The transition from a fully locked 170 km wide décollement to the unrestrained descending Indian plate occurs at ~25 km depth over an ~23 km wide transition zone. The convergence rate is consistent with the lower bounds of geological estimates for the Main Frontal Thrust, Riasi, and Balapora fault systems, on which no surface slip has been reported in the past millennium. Of the 14 damaging Kashmir earthquakes since 1123, none may have exceeded Mw = 7.6. Therefore, either a seismic moment deficit equivalent to a Mw ≈ 8.7 earthquake exists or the historical earthquake magnitudes have been underestimated. Alternatively, these earthquakes have occurred on reverse faults in the Kashmir Valley, and the décollement has been recently inactive. Although this can reconcile the inferred and theoretical moment release, it is quantitatively inconsistent with observed fault slip in Kashmir

Geodetic constraints on the translation and deformation of India: implications for future great Himalayan earthquakes

Because the elastic deformation of rock is fundamental to the earthquake process, geodetic surface measurements provide a measure of both the geometrical parameters of earthquake rupture, and a measure of the temporal and spatial development of elastic strain prior to rupture. Yet, despite almost 200 years of geodesy in India, and the occurrence of several great earthquakes, the geodetic contribution to understanding future damaging earthquakes in India remains minor. Global Positioning System (GPS) geodesy promises to remedy the shortcomings of traditional studies. Within the last decade, GPS studies have provided three fundamental constraints concerning the seismogenic framework of the Indian Plate: its overall stability < 0.01 μstrainlyear), its velocity of collision with Asia (58 ± 4 mm/year at N44E), and its rate of collision with southern Tibet (20.5 ± 2 mm/year). These NE directed motions are superimposed on a secular shift of the Earth's rotation axis. As a net result, India currently moves southward at 8 ± 1 cm/ year. In the next few decades we can expect GPS measurements to illuminate the subsurface distribution and rate of development of strain in the Himalaya, the relative contributions of along-arc and arc-normal deformation in the Himalaya and southern Tibet, and perhaps the roles of potential energy, plastic deformation and elastic strain in the earthquake cycle