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Which of the following statements is incorrect?
The Richter scale, developed by Charles Richter, is a logarithmic scale where each whole number increase represents a ten-fold increase in measured wave amplitude and roughly 32 times more energy release. It is a quantitative measure of the earthquake's size at its source. Intensity, however, is a qRead more
The Richter scale, developed by Charles Richter, is a logarithmic scale where each whole number increase represents a ten-fold increase in measured wave amplitude and roughly 32 times more energy release. It is a quantitative measure of the earthquake’s size at its source. Intensity, however, is a qualitative measure of how much the ground shook at a specific location, which varies depending on distance from the focus. Therefore, while we use a seismograph (instrument) to get the data, we use the Richter scale (calculation) to categorize the magnitude. Conflating “instrument” with “scale” and “magnitude” with “intensity” makes (B) incorrect.
See lessWhat are the ocean waves generated by underwater earthquakes called? (A) Scale (B) Kem (C) Cirque (D) Tsunami
A tsunami is not a single wave but a series of waves caused by the displacement of a large volume of water. When an undersea earthquake occurs at a subduction zone, the seafloor snaps upward or downward, pushing the water column above it. This creates a wave that can travel across entire oceans at sRead more
A tsunami is not a single wave but a series of waves caused by the displacement of a large volume of water. When an undersea earthquake occurs at a subduction zone, the seafloor snaps upward or downward, pushing the water column above it. This creates a wave that can travel across entire oceans at speeds exceeding 800 km/h (speed of a jet plane). Unlike normal tide-driven waves, tsunamis have extremely long wavelengths. As they approach the shore, the front of the wave slows down due to friction with the seabed, causing the back of the wave to pile up, resulting in a surge that can penetrate kilometers inland.
See lessWhich of the following is the main cause of tsunamis? (A) Cyclone (B) Anticyclone (C) Volcano (D) Earthquake
While volcanic eruptions or underwater landslides can cause tsunamis, approximately 80% to 90% are triggered by seismic activity. For a tsunami to occur, the earthquake must be of high magnitude (usually above 7.0) and must involve vertical movement of the crust. Horizontal (strike-slip) earthquakesRead more
While volcanic eruptions or underwater landslides can cause tsunamis, approximately 80% to 90% are triggered by seismic activity. For a tsunami to occur, the earthquake must be of high magnitude (usually above 7.0) and must involve vertical movement of the crust. Horizontal (strike-slip) earthquakes, like those on the San Andreas Fault, rarely cause tsunamis because they don’t displace the water upwards. The sudden “rebound” of the overriding plate at a subduction trench acts like a giant paddle, pushing the ocean and creating a wave that carries immense energy across thousands of miles.
See lessIn which of the following belts do most of the world’s earthquakes (approximately 63%) occur?
The Ring of Fire is home to the world's most dangerous subduction zones. Here, the Pacific Plate is constantly colliding with and sliding beneath surrounding plates like the Eurasian, North American and Philippine plates. This constant grinding and subduction build up massive amounts of elastic straRead more
The Ring of Fire is home to the world’s most dangerous subduction zones. Here, the Pacific Plate is constantly colliding with and sliding beneath surrounding plates like the Eurasian, North American and Philippine plates. This constant grinding and subduction build up massive amounts of elastic strain, leading to frequent and high-magnitude earthquakes. Countries along this belt, such as Japan, Chile, the Philippines and the western United States (Alaska and California), are at constant risk. This zone also contains about 75% of the world’s active volcanoes, illustrating the intense tectonic and magmatic activity that defines this “circum-Pacific” horseshoe-shaped region.
See lessEarthquakes affect not only continental areas but also oceanic areas, generating powerful waves in the oceans. By what name are these waves known?
When an earthquake affects the oceanic crust, the resulting water displacement creates a wave with a wavelength that can be over 100 kilometers long. In the open ocean, these waves are barely noticeable to ships because their height is low. However, they possess a "deep-water" energy that extends toRead more
When an earthquake affects the oceanic crust, the resulting water displacement creates a wave with a wavelength that can be over 100 kilometers long. In the open ocean, these waves are barely noticeable to ships because their height is low. However, they possess a “deep-water” energy that extends to the seafloor. As this energy enters the shallow continental shelf, “shoaling” occurs—the wave height increases dramatically while the speed drops. This results in a “Tsunami,” a destructive surge that can wash away entire coastal cities, as seen in the catastrophic 2004 Indian Ocean and 2011 Tohoku events.
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