jAmaSeis

jAmaSeis facilitates the study of seismological concepts in middle school through introductory undergraduate classrooms. Users can obtain and display seismic data in real-time from either a local instrument or from remote stations. Users can also filter data, fit a seismogram to travel time curves, triangulate event epicenters on a globe, estimate event magnitudes, and generate images showing seismograms and corresponding calculations. Users accomplish these tasks through an interface designed specifically for educational use.


Keypoints:

  • Stream View- The helicorder screen now has the flexibility to display up to three streams of data simultaneously. These can include a local educational seismometer, a remote educational seismometer over the jAmaseis network (in true real-time), or research-quality seismometers stored at the IRIS Data Management Center (in near real-time).
  • Computing Magnitude- For each stream, an event can be extracted allowing the user to pick amplitudes to calculate either a body wave or surface wave magnitude.
  • Computing Distance- For each stream, an event can be extracted allowing the user to pick arrivals by double-clicking on the seismogram. A travel time curve is available to align the picks, and as the seismogram is slid along the travel time curve, the numeric values update and a circle with the appropriate radius is shown on the globe.
  • Event View- All of the analysis for an earthquake comes together in the event view. Multiple traces can be loaded, either from the stream view or from a sac file. All of the individual distance calculations are displayed in both table and map form in addition to the individual magnitude calculations. In this view, a user can make the final determination of the location and size of the earthquake.

 

CLICK OPEN RESOURCE TO REGISTER AND DOWNLOAD NOW! 

Related Animations

The "moment magnitude" scale has replaced the Richter scale for large earthquakes. Scientists have developed far-more sensitive seismometers that, with faster computers, have enabled them to record & interpret a broader spectrum of seismic signals than was possible in the 1930's, when the Richter magnitude was developed. Find out what scientists learn from seismograms.

Animation of the principles of a drum-style horizontal seismograph station that records back- and-forth (N-S, E-W) movement.

Animation of the principles of a drum-style vertical seismograph station that records up-and-down movement.

Seismic waves travel through the earth to a single seismic station. Scale and movement of the seismic station are greatly exaggerated to depict the relative motion recorded by the seismogram as P, S, and surface waves arrive.

We use a cow and a tree in this narrated cartoon for fun and to emphasize that seismic waves traveling away from an earthquake occur everywhere, not just at seismic stations. Watch them shake as they are struck by incoming P, S, and Surface waves.

A cow and a tree in this narrated cartoon for fun and to emphasize that seismic waves traveling away from an earthquake occur everywhere, not just at seismic stations A, B, C, and D. A person would feel a large earthquake only at station A near the epicenter. Stations B, C, D, and the cow are too far from the earthquake to feel the seismic waves though sensitive equipment records their arrival.

This companion to the animation "Four-Station Seismograph network"  shows the arrival of seismic waves through select wave paths through the Earth (P and S waves) and over the surface of the Earth. The movement at distant stations occurs at a microscopic scale. While that doesn't result in noticeable movements of the buildings, the arrivals are recorded on sensitive seismometers.

A gridded sphere is used to show a single station recording five equidistant earthquakes.

A gridded sphere is used to showt: 1) the seismic stations don't need to be lined up longitudinally to create travel-time curves, as they appear in the first animation, and 2) a single station records widely separated earthquakes that plot on the travel-time curves.

A travel time curve is a graph of the time that it takes for seismic waves to travel from the epicenter of an earthquake to the hundreds of seismograph stations around the world. The arrival times of P, S, and Surface waves are shown to be predictable. This animates an IRIS poster linked to this animation.

Seismic shadow zones have taught us much about the inside of the earth. This shows how P waves travel through solids and liquids, but S waves are stopped by the liquid outer core.

The wave properties of light are used as an analogy to help us understand seismic-wave behavior.

The shadow zone is the area of the earth from angular distances of 104 to 140 degrees from a given earthquake that does not receive any direct P waves. The different phases show how the initial P wave changes when encountering boundaries in the Earth.

The shadow zone results from S waves being stopped entirely by the liquid core. Three different S-wave phases show how the initial S wave is stopped (damped), or how it changes when encountering boundaries in the Earth. 

Related Fact-Sheets

A seismograph is a device for measuring the movement of the earth, and consists of a ground-motion detection sensor, called a seismometer, coupled with a recording system. This fact sheet provides an overview of the basic components of a seismometer and physical science principles behind its operation.

Keep tabs on current seismicity with IRIS's Seismic Monitor. This fact sheet provides an introduction to an interactive display of global seismicity that allows users to monitor earthquakes in near real-time, view records of ground motion, learn about earthquakes, and visit seismic stations around the world.

Many people associate earthquakes with destruction caused by falling buildings or by the creation of a tsunami. While earthquakes may be associated with destruction in the time frame of human activity, in the evolution of the Earth they signal the geological forces that build our mountains and create our oceans. This fact sheet provides an introduction to the causes of earthquakes.

Earthquakes create seismic waves that travel through the Earth. By analyzing these seismic waves, seismologists can explore the Earth's deep interior. This fact sheet uses data from the 1994 magnitude 6.9 earthquake near Northridge, California to illustrate both this process and Earth's interior structure.

Knowing precisely where an earthquake occurred is an important piece of scientific information. It can help seismologists identify and map seismic hazards. It is also a fundamental piece of information necessary for facilitating studies of Earth's internal structures. This fact sheet provides an overview of the S-P process to locate an earthquake.

A seismograph is a device for measuring the movement of the earth, and consists of a ground-motion detection sensor, called a seismometer, coupled with a recording system. This fact sheet provides an overview of the basic components of a seismometer and physical science principles behind its operation.

Related Videos

The arrival times of P and S waves are used to determine the distance to an earthquake using standard travel-time curves. 

jAmaSeis is a free, java-based program that allows users to obtain and display seismic data in real-time from either a local instrument or from remote stations. This video walks you through the steps to set it up on your computer.

Related Software-Web-Apps

A beautiful map of the latest earthquakes in near-real time. The map also provides links to related resources, news, and connections to 3D maps.

The IRIS Earthquake Browser (IEB) is an interactive map for exploring millions of seismic event epicenters (normally earthquakes) on a map of the world. Selections of up to 5000 events can also be viewed in 3D and freely rotated with the 3D Viewer companion tool.

The Searchable Product Depository (SPUD) is the IRIS DMC's primary data product management system. Complementing the DMC's SEED and assembled data archives, which contain time series recordings, the SPUD system primarily contains derivative data products of other types (images, movies, etc.) created either at the DMC or by members of the community.

Related Lessons

To understand plate tectonic processes and hazards, and to better understand where future earthquakes are likely to occur, it is important to locate earthquakes as they occur. In this activity students use three-component seismic data from recent earthquakes to locate a global earthquake.

Related Posters

Seismic waves from earthquakes ricochet throughout Earth's interior and are recorded at geophysical observatories around the world. The paths of some of those seismic waves and the ground motion that they caused are used by seismologists to illuminate Earth's deep interior.

The Global Seismographic Network (GSN) consisting of more than 125 seismic stations provides data for scientific research, education, earthquake hazard mitigation, tsunami warning, and the international monitoring system for the Comprehensive Nuclear Test-Ban Treaty.