GeoMapApp© Help
Seafloor Earthquakes and Volcanic Eruptions
The Pacific Marine Environmental Lab of NOAA (PMEL) has provided seismicity data recorded as 't' waves from moored hydrophone stations.
There are datasets from three regions:
Juan de Fuca Ridge in the northeast Pacific Ocean
East Pacific Rise in the eastern central Pacific Ocean
Mid-Atlantic Ridge in the Atlantic Ocean
Select a region, choose a data set, then press OK or load if changing data sets.
In this window the toolbar zoom icon has been used to enlarge the Juan de Fuca Ridge region as shown in the Main Map Window in the upper left. The red squares are earthquake epicenter locations.
In the lower panel the earthquakes are displayed as a function of time from left to right. Pressing the play button causes the earthquakes to be displayed as decaying warm colors within the Main Map Window in the order they occurred. The sequence can be recorded as a Quicktime movie by choosing the display rate in frames per second then pressing the Save button. Note: problems viewing the movie have been reported by Macintosh users.
One can grab and move the two vertical date bars to select the time span of the earthquakes shown in the display window. Only the earthquakes that occurred in the new time span are displayed in the Main Map Window.
In this way one can zoom in on an earthquake swarm and watch the epicenters move along the mid-ocean ridge axis during dyke migration.
"Control" and click zooms in on a shorter time period. "Control" "shift" and click zooms out to a longer time period. The reset button expands the time window back to the full period of recording.
When finished viewing earthquakes, press the close button to release computer memory and improve performance for other viewing options.
