In this Incorporated Research Institutions for Seismology resource we look at a demonstration comparing layers of the earth to layers of hard-boiled egg.

Roger Groom, science teacher at Mount Tabor Middle School, demonstrates how a slinky is a good analogy for P & S seismic waves. He also points out where the model fails to fully mimic seismic-wave behavior

This animation of a part of Alan L. Jones' Seismic Waves program works was produced by R.Welti, IRIS. The 2004 Sumatra generated seismic waves that traveled through and around the globe. The seismic waves were recorded on the seismic stations shown on the animation. Watch the seismograms at the top of the animation develop with time. Notice that the further from the earthquake is, not only to the first waves arrive later, but the time between the P and S waves is increasing.

In this Incorporated Research Institutions for Seismology resource we look at the four basic types of plate tectonic boundaries.

In this Incorporated Research Institutions for Seismology resource we look at how to design a structure to withstand an earthquake, including using simple materials to engineer shear walls.

In this Incorporated Research Institutions for Seismology resource we look at faults and folds.

In this Incorporated Research Institutions for Seismology resource we look at how tectonic plates. Lithospheric plates have two parts consisting of crust and upper mantle.

In this Incorporated Research Institutions for Seismology resource we look at how scientists determine where an earthquake occurred and the difference between the epicenter and the focus (hypocenter).

This video shows seismic waves from the Haiti earthquake traveling across a series of seismic stations that are deployed in the US.

In this Incorporated Research Institutions for Seismology resource we look at a three-dimensional inversion of EarthScope magnetotelluric data and crustal and mantle conductivity beneath the NW USA.

Animation addresses 5 common variations of P-type seismic body waves. All are compressive waves that travel through the Earth in all directions away from the epicenter of an earthquake. The different phases show how the initial P wave changes when encountering boundaries in the Earth

Introduction to refraction. Seismic waves follow the same law of refraction at compositional boundaries. If the seismic wave velocity in the rock below a boundary increases,the waves will be refracted upward and speed up relative to their original path

This animation shows seismic waves from a recent earthquake moving across a series of stations in the US.

Relative motion of the subducting plate assuming no friction between the plates

No Audio: The animation shows how sound waves, emitted by an energy source towed beneath a boat, are reflected off substrates at depth and are recorded and interpreted by seismologists. Seismologists collect data as sound and seismic waves are transmitted through the Earth and reduce the data to 'squiggles'. They interpret the images to see changes in rock layers at depth. This animation from a collection of New Madrid seismic-zone animations:

the first of three narrated demonstrations of seismic resonance and why certain buildings fall during earthquakes. This is the simplest and easiest with minimal preparation. 'Resonance3-dowel-Large.mov' is the most descriptive and is worth the effort. Dr. John C. Lahr, USGS emeritus seismologist, demonstrates the concept using three different methods.

In this Incorporated Research Institutions for Seismology resource we look at seismic tomography, an imaging technique using earthquakes to create three-dimensional images of the inside of the Earth.

A nearby seismograph station records an elk running. Even a sensitive station cannot detect this type of surface thumping at a distance.

In this Incorporated Research Institutions for Seismology resource we look at cows bouncing and rolling above the surface of the Earth. This motion is exaggerated. The intent was to illustrate the nature of wave movement, not mimic reality. This second cartoon, not narrated, was designed as a better approximation to reality. It shows the arrival of seismic waves through select wave paths through the Earth (P and S waves) and over the surface of the Earth.

In this Incorporated Research Institutions for Seismology resource we look at how a 3-component seismogram works.

In this Incorporated Research Institutions for Seismology resource we look at the brittle vs. ductile character of the layers of the earth using a Big Hunk chocolate.