III. RESULTS AND DISCUSSION:
Fig. 1 shows the map of a part of Asia in which the stars indicate the location of earthquakes and solid circle indicates the location of observing station Agra (27.2o N, 78o E). The details of these earthquakes are mentioned in table 1 which shows the days of occurrence, magnitudes, depths (km), locations (Latitude and Longitude in degrees), radius of influence zone (km) and distances from the Agra station (km). The radius of influence zone is calculated by using the expression R = 100.43M, where M is the magnitude of the earthquake [21]. Although these earthquakes have occurred far away from the observing station Agra, atleast two of them are well covered (> 1000 km) by the radius of the influence zone. The details of the earthquake data have been taken from United States Geological Survey (USGS) website www.earthquake.usgs.gov.in. We have also seen the variations of geomagnetic parameters such as Dst index and ∑ Kp index for each case separately and data have been taken from National Aeronautics and Space Administration (NASA) website http://omniweb.gsfc.nasa.gov/form/dx1.html. We can see from table 1 that all the earthquakes have shallow depths except one of them (46 km), but we cannot ignore this earthquake because of its relatively large magnitude (M = 7.8). Further, it may be seen from the table 1 that two of the earthquakes occurred in the month of April, one in July, and rest two in September, 2013.
The top two panels of Fig. 2 show the day to day variation of GPS-TEC for the month of April 2013 as observed at Agra station. Here, the vertical-TEC is shown by dotted line and the corresponding sum (m + σ) and difference (m – σ) are shown solid and dashed lines respectively. The days of occur...
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...thquakes, the anomalous variations in TEC cannot be attributed to these factors. The only reason for anomalies are the earthquakes which is supported by statistical analysis also.
IV. CONCLUSIONS
In this paper, we analyze the three months GPS-TEC data corresponding to five major earthquakes around the Indian Subcontinent and the statistical analysis is used for the better interpretation of results. The findings of our study are as follows; we have found the enhancements in TEC as the precursors of major earthquakes around Indian subcontinent but these results are in contrast with the results of other workers [4]-[6] who have found the depletions also. This contrast in results may be caused by latitude dependence and the enhancements in TEC data caused by the upward electric field which penetrates the ionosphere eastward according to the mechanism mentioned above.
Earthquakes are a natural part of the Earth’s evolution. Scientific evidence leads many geologists to believe that all of the land on Earth was at one point in time connected. Because of plate tectonic movements or earthquakes, continental drift occurred separating the one massive piece of land in to the seven major continents today. Further evidence supports this theory, starting with the Mid-Atlantic ridge, a large mass of plate tectonics, which are increasing the size of the Atlantic Ocean while shrinking the Pacific. Some scientists believe that the major plate moveme...
could be used to explain and illustrate that previous theories were not entirely correct (Merali and Skinner, 2009, p.253). Through the analyzation of arrival times of these waves, Oldham had drawn an conclusion that p waves and s waves react differently in terms of being refracted, reflected or absorbed depending on the state of the material as shown in Figure 1.(Tarbuck, Lutgens, Tasa, 2013, p.143). Oldham had developed this theory of the Earth not being the same state due to these effects of seismic discontinuity which are shown in Figure 1., consisting of refraction, reflection and absorption. The changes that are displayed from this idea are; the speed of the waves due to a refraction occu...
With the recent earthquakes in California, many are worried about the next earthquake that could be the potential “big” one that many geologists have been predicting for many years. The Cascadia subduction zone is also known as the CSZ megathrust fault. It is roughly 1000km long, a dipping fault that stretches from the Northern Vancouver Islands to Cape Mendocino, California. The zone passes through British Columbia, Washington, Oregon and into California. The Cascadia region has experienced several types of earthquakes and it is very likely to experience similar quakes in the near future.
The other statement is that the New Yorker reported FEMA calculations that indicate that the massive mega quakes happen at regular intervals in the Pacific Northwest roughly every 240 years. Based on this statement, it implies that there has not been frequent massive mega quakes. However, geologists and paleologists can ascertain that massive mega quakes in the Pacific Northwest are usually often. Therefore, the geologists and paleologists do not concur with the statement.
Problem Statement: Earthquakes are a natual part of the environment. They do,however,cause devistating effect on the environment. Since Earthquakes can not be avoided, maybe there is a way to determine when they are going to occur so precautions can be taken to get people to safety and protect as much of
Before examining the Northridge event, understanding the naturally occurring hazard that is an earthquake will help to better understand exactly what happened and why it was such an important geological event. With four distinct layers, two layers, the crust and upper portion of the mantle, compose the skin that is the surface layer of the Earth. The crust is not a single, continuous piece. It is actually several different pieces, or plates, that come together to form the puzzle that comprises the surface of the Earth. These plates are in constant motion rubbing against one another. These areas, known as fault lines, where the plates rub up against one another have spots where one plate ”gets stuck while the rest of the plate keeps moving. When the plate has moved far enough, the edges unstick and is how most of the earthquakes around the world occur” (Wald, 2012). The energy stored from the friction of the two plate...
What have they learned since the quake quite allot. The fault moved in a fashion that geologists of
Intro: The Global Positioning System (GPS) is a navigation system that provides information such as location, speed and time anywhere around the world. The GPS is a network of approximately 30 satellites constantly orbiting the earth. These satellites can precisely pinpoint the location of a GPS receiver anywhere around the world. The introduction of this new technology which can be used for many purposes has changed society and the environment both positively and negatively.
The following is a brief illustration of the principles of GPS. For more information see previous chapter. The Global positioning System (GPS) is a satellite-base navigation system that provides a user with proper equipment access to positioning information. The most commonly used approaches for GPS positioning are the Iterative Least Square (ILS) and the Kalman Filter (EKF) methods. Both of them are based on psuedorange equation:
The Tohoku earthquake caused by the movement of the Pacific plate slides underneath the Eurasia plate at the rate of three inches per year, associated with Japan Trench
From modern examples and records we know that volcanic activity can set of a chai...
The Library of Congress (2011). What is a GPS? How does it work? [online] Available at: http://www.loc.gov/rr/scitech/mysteries/global.html [Accessed 16th April, 2014]
The 6.7 magnitude earthquake was felt throughout most of southern California and as far away as Utah and Mexico with a max acceleration of 1.0g in several different areas and the highest at Tarzana with a recorded value of 1.8g. The earthquake also deformed over 1500 square miles of the Earth’s crust, forcing the surface upward in a dome shape. The Susana Mountains sustained the most soil deformation with an uplift of around 15cm causing numerous rockslides, blocking many roadways. Soil liquefaction was observed in the Simi Valley area and other parts of the Los Angeles Basin. After all the term oil ended the preliminary cost estimate of damage was between 15 and 20 billion U.S. dollars. Today, Geologists remain to search for thrust faults throughout the southern California area by using a 3 dimensional modeling system to view folds and upli...
There are about 31 active satellites used for GPS communication which are rotating around the earth’s axis. Their orbit is inclined 55 degrees with respect to the equator. Satellites are placed at 20,000 kilometers from the earth’s surface and their orbits are designed in such a way that each satellite rotates two orbits per day. Orbits are planned so that at least 6 satellites in view, from most area on the earth [4].
Earthquakes belong to the class of most disastrous natural hazards. They result in unexpected and tremendous earth movements. These movements results from dissemination of an enormous amount of intense energy in form of seismic waves which are detected by use of seismograms. The impact of earthquakes leaves behind several landmarks including: destruction of property, extensive disruption of services like sewer and water lines, loss of life, and causes instability in both economic and social components of the affected nation (Webcache 2).