Vertical Datum

17. Plot the earthquake data from the region associated with the Peru-Chile Trench from Table 1 on the right section of the graph paper, using a dot to represent each data point.

Also, ground deformation involves the movement of magma within the lithosphere can deform the ground above, this has been witnessed at Yellowstone beneath Yellowstone Lake. This swelling of the volcano signals that magma has collected near the surface. Scientists monitoring an active volcano will often measure the tilt of the slope and track changes in the rate of swelling. Mount St Helens showed this prior to its eruption in 1980. Both magma movement, changes in gas release and hydrothermal activity can lead to thermal emissivity changes at the volcano's surface. We can use satellite imagery, activity of minor extrusive features such as geysers and hot springs and mapping to monitor this. Finally, Remote sensing is the use of satellites to detect things about the Earth’s surface. This is useful for monitoring any changes in volcanoes at the surface. Using satellites we can monitor the thermal activity of the volcano to check for upwelling magma, we can check for escaping Sulphur dioxide using gas sensing and we can look to see if the ground is deforming by checking before and after images of the ground. The satellite can also judge if the ground is being uplifted by measuring the distance between the satellite and the ground.

To support the theory of continental drift is through topography, surveying the floors of oceans, charts of rock magnetism, and statistics on rock ages (Trefil & Hazen, 2010). At one time scientist believed that the deep ocean floors were flat; accumulating the sediment that progressively wore away from the prehistoric landmasses (Trefil & Hazen, 2010). However, they discovered steep-walled valleys and elevated highlands. This was evidences that just as the continents are transformed and are active, so to is the seafloor (Trefil & Hazen, 2010). The Mid- Atlantic Ridge, positioned in the central part of the Atlantic Ocean, is recorded to be the longest mountain range on this planet. Volcanoes, lava flow, and earthquakes are a source of

The 1906 San Francisco Earthquake tectonic setting was in the outermost shell of earth known as the crust this is composed of rigid plates that have been moving for hundreds of millions of years. Two of these moving plates meet in western California; the boundary between them is a zone of faults, the principal one being the San Andreas fault. The horizontal sliding of the Pacific Plate relative to the North American Plate, causes earthquakes along the San Andreas fault and similar plates near the region. The San Andreas fault is a transform plate boundary, accommodating horizontal relative motions (usgs.gov).

At least 3 earthquake recording stations are required to find the location of the earthquake epicenter. A single recording station can only calculate distance, but not direction; to cover all possibilities, a complete circle is drawn around that station. If only two earthquake recording stations are used, the circles will overlap at two points. Data from a third recording station will eliminate one of these points.

S- together the angles make a coordinate that can pinpoint any geographic position on the surface of the Earth, or any other

The earthquake was felt from southern Oregon to south of Los Angeles and inland as far as central Nevada, an area of approximately 200,000 square miles. The ground motion caused by the earthquake source is recorded by instruments called seismographs. The zigzag trace made by a seismograph, called a "seismogram," reflects the changing amplitude and frequency content of the ground shaking beneath the instrument (usgs.gov). Using seismograms, scientists can determine the time, the epicenter, the depth, and the type of faulting of an earthquake as well as estimate how much energy was released by it.

What are coordinate and projection systems, and what is their purpose in defining geographic information?

water fractures within the earth. Causing certain areas of the land to have an earthquake effect

earthquakes (Google Search). They are essential to figuring out a possible eruption based on the

Earthquake early warning systems alert devices and people when shaking waves generated by an earthquake are expected to arrive at their location. The seconds to minutes of advance warning allow people and systems to take actions to protect life and property from disastrous shaking. Devices such as isolation systems and dampers are designed to reduce vibrations of structures being effected in an earthquake and are added to the design of some modern buildings mainly in Japan. Advanced radar and infrared cameras take a series of images collecting data to identify signs of earthquakes. Advanced Interferometric Synthetic Aperture Radar shows fault movements over a period of years. Modems and Data Processing centres receive data collected by satellites to analyse the trends recognised in the electromagnetic emissions, radar pictures, infrared readings and elf

The energy coming from this rupture is called seismic waves. These waves fan out in every direction from the earthquakes epicenter and results in intense shaking. Once this shaking reaches the earth’s surface, everything from the ground up will also proceed to shake (Wald 2012). In order to measure the size of an earthquake, scientists use seismographs. Seismographs consist of a base, a spring, pen, rotating drum, and a heavy weight. The base is placed in the ground while the weight hangs above. When an earthquake occurs the spring absorbs the shaking and the weight and pen, which remain motionless, record the difference between the shaking and motionless part of the seismograph. Seismograph recordings consist of short and long wavy lines, with long lines indicating a larger earthquake (Wald 2012). These recordings are then

While liquid water is the most important factor, there are other geodynamical and geophysical features that are important.

“Data is plural of datum, which is the dates, numbers, ages, symbols, letters, and words that represent basic facts and observations about people, processes, measurements, and conditions.” To be useful, data must be accurate.

The San Andreas Fault is one of the most widely studied faults in the world. Scientists use an array of methods in collecting data and providing analysis of fault characteristics both past and present. Presently there are many differing hypothesis and models used to describe crustal movements and deformation within the Pacific and North American plate boundary. Historical earthquakes along this fault have proven to be rather large and devastating. This is important since the San Andreas Fault runs along many highly populated areas throughout Northern and Southern California. Through further research and analysis of this fault system scientists hope to solve