false. The velocity of a wave depends on the elastic properties and density of a material. Great progress was made quickly because for the most part Earth's interior is relatively simple, divided into a sphere (the inner core) surrounded by roughly uniform shells of iron and rock. Although temperature also increases with depth, the pressure increase resulting from the weight of the rocks above has a greater impact and the speed increases smoothly in these regions of uniform composition. Rayleigh waves are the slowest of all the seismic wave types and in some ways the most complicated. At a seismic station the first waves to arrive are _____. Likewise, when an S-wave interacts with a boundary in rock properties, it too generates reflected and refracted P- and S-waves. In practice we use better estimates of the speed than our simple rule of thumb and solve the problem using algebra instead of geometry. Another important characteristic of Love waves is that the amplitude of ground vibration caused by a Love wave decreases with depth - they're surface waves. Also, note that the correlation with surface tectonics is gone, as you would expect for a complex convective system such as Earth's mantle. The point on the surface of the Earth at which a seismic wave first hits is called the epicenter. The change in direction depends on the ratio of the wave velocities of the two different rocks. In fact, we often divide the mantle into two regions, upper and lower, based on the level of velocity heterogeneity. When waves reach a boundary between different rock types, part of the energy is transmitted across the boundary. Seismic waves can be distinguished by a number of properties including the speed the waves travel, the direction that the waves move particles as they pass by, where and where they don't propagate. A seismic wave is an elastic wave generated by an impulse such as an earthquake or an explosion. Fast. They typically travel at speeds between ~1 and ~14 km/sec. parallel: Having the same direction. Which type of wave can penetrate the outer and inner core? Which seismic wave refracts and cannot penetrate the core? The second wave interaction with variations in rock type is reflection. In general, earthquakes generate Love waves over a range of periods from 1000 to a fraction of a second, and each period travels at a different velocity but the typical range of velocities is between 2 and 6 km/second. A seismic reflection occurs when a wave impinges on a change in rock type (which usually is accompanied by a change in seismic wave speed). And we're going to focus on one more than the other. Properties of seismic waves. 5. I mentioned above that surface waves are dispersive - which means that different periods travel at different velocities. In some instances reflections from the boundary between the mantle and crust may induce strong shaking that causes damage about 100 km from an earthquake (we call that boundary the "Moho" in honor of Mohorovicic, the scientist who discovered it). These variations are actually quite small, on the order of a few percent, so the basic idea of Earth being a spherically stratified planet are well founded. After both P and S waves have moved through the body of Earth, they are followed by surface waves, which travel along Earth’s surface. At a seismic station the second waves to arrive are _____. T/F. The diagram below is an example of the paths P-waves generated by an earthquake near Earth's surface would follow. Well, they affect the foundations of buildings and cause them to topple. Earthquakes are imperfect illuminators because they are clustered on plate boundaries, leaving much of the interior in the shadows. The effects of dispersion become more noticeable with increasing distance because the longer travel distance spreads the energy out (it disperses the energy). If we have two other seismometers which recorded the same earthquake, we could make a similar measurement and construct a circle of possible locations for each seismometer. Similar waves, which are generated by earthquakes, artificial explosions and analogous sources, and pr~pagate along the Earth's surface, are referred to as seismic surface waves. Pressure increases with depth in Earth because the weight of the rocks above gets larger with increasing depth. Seismic waves. Assume a seismometer are is far enough from the earthquake that the waves travel roughly horizontally, which is about 50 to 500 km for shallow earthquakes. Seconds, etc. of rocks are imperfect illuminators because they cause most. 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