Webicorders are simply long seismograms that are "wrapped", much as a word processor wraps a long sentence or paragraph into many lines. They are useful for viewing seismic activity at a single station over a long period of time. HVO already provides a subset of stations in webicorder form. This interface is an experiment to try to serve all of our stations out. We are initially encouraged by the results and are eager to hear comments at webmaster@hvo.wr.usgs.gov.

Stations are shown with triangles. Click on a triangle to see the webicorders for that particular station. Only the vertical channel of the short period or broadband seismometer is typically available for each station due to processing constraints. The HVO consists of three principal types of stations:

• Short Period (SP, red): Seismic stations that are sensitive to frequencies above 1-2 Hz. Short period instruments are excellent for locating small earthquakes and tend to be robust in adverse conditions(like volcanoes).
• Broadband (BB, blue): Seismic stations that are sensitive to a broad range of frequencies, often down to 100 second periods or more. Good for analyzing large earthquakes at large distances, long-period earthquakes and for noise studies. In the HVO network, strong motion stations are often installed with broadband seismometers.
• Strong Motion (SM, black): Seismic stations that are built to stay on-scale even in the largest earthquakes at close distances. These stations are often located in buildings or school and are vital for studying the local effects of large earthquakes.

Several links are present for each station. The 6-hour link represents the current data the network has available. The 12 and 24 hour plots are updated hourly. The 6- hour links may be down during times of eruptions or moderate earthquakes. When clicking the 6 hour link, a white page with the message "Error: could not get helicorder data, check channel (code)." means that the station is broken and not reporting. This is normal. Other links for that station may also be broken.