A map of the new world is a picture of one of the most important results of the
war. Most people think of a map as a fixed thing. On the contrary, it is almost
as changeful as mankind itself.
-- Isaiah Bowman 1922
Wednesday, January 30, 2008
Urban Growth in India
Total urban population in India has increased more than ten times from 26 million in 1901 to 285 million in 2001 whereas total population has increased less than five times from 238 million to 1027 million from 1901 to 2001 respectively. In the same fashion the number of town had also increased from 1916 in 1901 to 2422 in 1951 and then to 4689 in 1991. About three-fold increase has been noticed for percentage of total urban population in Class-I city over the decades (1901 to 1991). While there was only one million plus city (Kolkata) in 1901 in
Conference on Women Empowerment
A Conference on Women Empowerment is going to be held at DAV Bulandshahr , India on 16-17 February,2008, All interested are requested to attend.You may contact to rashid.faridi@gmail.com.
Tuesday, January 29, 2008
GPS Systems
Global Positioning Systems (GPS) are space-based radio positioning systems that provide 24 hour three-dimensional position, velocity and time information to suitably equipped users anywhere on or near the surface of the Earth (and sometimes off the earth). Global Navigation Satellite Systems (GNSS) are extended GPS systems, providing users with sufficient accuracy and integrity information to be useable for critical navigation applications. The NAVSTAR system, operated by the U.S. Department of Defense, is the first GPS system widely available to civilian users. The Russian GPS system, GLONASS, is similar in operation and may prove complimentary to the NAVSTAR system.
These systems promise radical improvements to many systems that impact all people. By combining GPS with current and future computer mapping techniques, we will be better able to identify and manage our natural resources. Intelligent vehicle location and navigation systems will let us avoid congested freeways and find more efficient routes to our destinations, saving millions of dollars in gasoline and tons of air pollution. Travel abord ships and aircraft will be safer in all weather conditions. Businesses with large amounts of outside plant (railroads, utilities) will be able to manage their resources more efficiently, reducing consumer costs.
Naturally Occuring Earthquakes
Most naturally occurring earthquakes are related to the tectonic nature of the Earth. Such earthquakes are called tectonic earthquakes. The Earth's lithosphere is a patchwork of plates in slow but constant motion caused by the release to space of the heat in the Earth's mantle and core. The heat causes the rock in the Earth to flow on geological timescales, so that the plates move slowly but surely. Plate boundaries lock as the plates move past each other, creating frictional stress. When the frictional stress exceeds a critical value, called local strength, a sudden failure occurs. The boundary of tectonic plates along which failure occurs is called the fault plane. When the failure at the fault plane results in a violent displacement of the Earth's crust, energy is released as a combination of radiated elastic strain seismic waves, frictional heating of the fault surface, and cracking of the rock, thus causing an earthquake. This process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the Elastic-rebound theory. It is estimated that only 10 percent or less of an earthquake's total energy is radiated as seismic energy. Most of the earthquake's energy is used to power the earthquake fracture growth or is converted into heat generated by friction. Therefore, earthquakes lower the Earth's available elastic potential energy and raise its temperature, though these changes are negligible compared to the conductive and convective flow of heat out from the Earth's deep interior.
The majority of tectonic earthquakes originate at depths not exceeding tens of kilometers. In subduction zones, where older and colder oceanic crust descends beneath another tectonic plate, Deep focus earthquakes may occur at much greater depths (up to seven hundred kilometers). These seismically active areas of subduction are known as Wadati-Benioff zones. These are earthquakes that occur at a depth at which the subducted lithosphere should no longer be brittle, due to the high temperature and pressure. A possible mechanism for the generation of deep focus earthquakes is faulting caused by olivine undergoing a phase transition into a spinel structure.
Earthquakes also often occur in volcanic regions and are caused there, both by tectonic faults and by the movement of magma in volcanoes. Such earthquakes can serve as an early warning of volcanic eruptions.
Sometimes a series of earthquakes occur in a sort of earthquake storm, where the earthquakes strike a fault in clusters, each triggered by the shaking or stress redistribution of the previous earthquakes. Similar to aftershocks but on adjacent segments of fault, these storms occur over the course of years, and with some of the later earthquakes as damaging as the early ones. Such a pattern was observed in the sequence of about a dozen earthquakes that struck the North Anatolian Fault in
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes are recorded with a seismometer, also known as a seismograph. The moment magnitude of an earthquake is conventionally reported, or the related and mostly obsolete Richter magnitude, with magnitude 3 or lower earthquakes being mostly imperceptible and magnitude 7 causing serious damage over large areas. Intensity of shaking is measured on the modified Mercalli scale.
At the Earth's surface, earthquakes manifest themselves by a shaking and sometimes displacement of the ground. When a large earthquake epicenter is located offshore, the seabed sometimes suffers sufficient displacement to cause a tsunami. The shaking in earthquakes can also trigger landslides and occasionally volcanic activity.
In its most generic sense, the word earthquake is used to describe any seismic event—whether a natural phenomenon or an event caused by humans—that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by volcanic activity, landslides, mine blasts, and nuclear experiments.
An earthquake's point of initial rupture is called its focus or hypocenter. The term epicenter means the point at ground level directly above this.
Read More
At the Earth's surface, earthquakes manifest themselves by a shaking and sometimes displacement of the ground. When a large earthquake epicenter is located offshore, the seabed sometimes suffers sufficient displacement to cause a tsunami. The shaking in earthquakes can also trigger landslides and occasionally volcanic activity.
In its most generic sense, the word earthquake is used to describe any seismic event—whether a natural phenomenon or an event caused by humans—that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by volcanic activity, landslides, mine blasts, and nuclear experiments.
An earthquake's point of initial rupture is called its focus or hypocenter. The term epicenter means the point at ground level directly above this.
Read More
Synthetic Aperture Radar: SAR
Environmental monitoring, earth-resource mapping, and military systems require broad-area imaging at high resolutions. Many times the imagery must be acquired in inclement weather or during night as well as day. Synthetic Aperture Radar (SAR) provides such a capability. SAR systems take advantage of the long-range propagation characteristics of radar signals and the complex information processing capability of modern digital electronics to provide high resolution imagery. Synthetic aperture radar complements photographic and other optical imaging capabilities because of the minimum constraints on time-of-day and atmospheric conditions and because of the unique responses of terrain and cultural targets to radar frequencies.
Synthetic aperture radar technology has provided terrain structural information to geologists for mineral exploration, oil spill boundaries on water to environmentalists, sea state and ice hazard maps to navigators, and reconnaissance and targeting information to military operations. There are many other applications or potential applications. Some of these, particularly civilian, have not yet been adequately explored because lower cost electronics are just beginning to make SAR technology economical for smaller scale uses.
Synthetic aperture radar technology has provided terrain structural information to geologists for mineral exploration, oil spill boundaries on water to environmentalists, sea state and ice hazard maps to navigators, and reconnaissance and targeting information to military operations. There are many other applications or potential applications. Some of these, particularly civilian, have not yet been adequately explored because lower cost electronics are just beginning to make SAR technology economical for smaller scale uses.
Monday, January 28, 2008
India to share satellite data with SAARC countries
Pakistan, Bangladesh, Afghanistan and other SAARC nations will have access to free-of-cost remote sensing data collected by various satellites launched by the Indian Space Research Organisation (ISRO) during major disasters in the region.
"The modalities (of this arrangement) are being worked out which will be contingent on what exactly the participating countries would share and open up in lieu of having access to ISRO's data," said a senior home ministry official, adding that the in principle decision has been taken and would be ratified by the Union Cabinet in due course.
Experts from the SAARC countries were informed of this decision on Monday when they assembled here for a regional workshop on application of science and technology for disaster risk reduction management, inaugurated by Union home minister Shivraj Patil.
The official said since the satellite imaging of the region also involves the security concerns of the neighbouring countries, it would be discussed with each nation concerned. India has more than half a dozen operational remote sensing satellites in orbit covering the entire SAARC region.
The idea, as discussed in the workshop, is to use geo-informatics in risk-mapping, risk assessment and risk monitoring under diverse geographical, socio-economic and cultural settings. Indian experts specifically mentioned how remote sensing images taken even by commercial satellites clearly captured the tsunami along the eastern coast (2004), Kashmir earthquake (2005) and Bangladesh cyclone 'Sidr' (2007).
Experts felt that sharing of such data would not only help in assessing the actual damages/sufferings due to disasters but also help in improving transparency in relief and rehabilitation administration in the entire region.
During his inaugural address, the home minister also called upon the South Asian nations to use their strength in science and technology to build a robust system of prevention, mitigation and preparedness to reduce the risks of natural and man-made disasters.
Drawing attention of experts to the fact that various regions of the sub-continent are prone to earthquakes, Patil stressed the need for sustained scientific research on earthquake, particularly in the Himalayan region, so as to be able to identify the fault zones and the return period more accurately.
While discussing the issue, Indian experts later informed the participants about the possibility of using IIT, Roorkee, as a nucleus to form a thematic network in the region with a nodal agency in each SAARC country for sharing of information to deal with earthquakes.
full story
"The modalities (of this arrangement) are being worked out which will be contingent on what exactly the participating countries would share and open up in lieu of having access to ISRO's data," said a senior home ministry official, adding that the in principle decision has been taken and would be ratified by the Union Cabinet in due course.
Experts from the SAARC countries were informed of this decision on Monday when they assembled here for a regional workshop on application of science and technology for disaster risk reduction management, inaugurated by Union home minister Shivraj Patil.
The official said since the satellite imaging of the region also involves the security concerns of the neighbouring countries, it would be discussed with each nation concerned. India has more than half a dozen operational remote sensing satellites in orbit covering the entire SAARC region.
The idea, as discussed in the workshop, is to use geo-informatics in risk-mapping, risk assessment and risk monitoring under diverse geographical, socio-economic and cultural settings. Indian experts specifically mentioned how remote sensing images taken even by commercial satellites clearly captured the tsunami along the eastern coast (2004), Kashmir earthquake (2005) and Bangladesh cyclone 'Sidr' (2007).
Experts felt that sharing of such data would not only help in assessing the actual damages/sufferings due to disasters but also help in improving transparency in relief and rehabilitation administration in the entire region.
During his inaugural address, the home minister also called upon the South Asian nations to use their strength in science and technology to build a robust system of prevention, mitigation and preparedness to reduce the risks of natural and man-made disasters.
Drawing attention of experts to the fact that various regions of the sub-continent are prone to earthquakes, Patil stressed the need for sustained scientific research on earthquake, particularly in the Himalayan region, so as to be able to identify the fault zones and the return period more accurately.
While discussing the issue, Indian experts later informed the participants about the possibility of using IIT, Roorkee, as a nucleus to form a thematic network in the region with a nodal agency in each SAARC country for sharing of information to deal with earthquakes.
full story
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