Webicorder Samples

Local Earthquakes


Local earthquakes of all sizes are recorded at every station, but may not be large enough to “trigger” our network and allow us to locate them. If an earthquake is very small and local to one or two stations, you may see its recording only on those stations. Check the time of the earthquake’s beginning (the origin time) to make sure you are looking at the same earthquake at each station.

Local earthquake example Local earthquake example
A local earthquake of magnitude 3.0 with many smaller earthquakes recorded by station LOHW. A local earthquake of magnitude 2.3 recorded by station MTPU.

Distant Earthquakes


Large teleseisms from all over the world may be recorded on all stations. See the list of worldwide earthquakes available at the National Earthquake Information Center.

 Teleseism earthquake example A teleseism (earthquake more than 1000 kilometers distant) recorded by station LCMT.

Teleseism earthquake example
A teleseism (earthquake more than 1000 kilometers distant) recorded by station LCMT.

Other


Station NAIU at Antelope Island, Utah is sensitive to wind. This is several night-time hours of wind generated noise. Station ICU in Indian Springs Canyon, Utah and some of the Yellowstone National Park stations are also sensitive to wind.

Telemetry noise at GZU can be caused by the buildup of ice on the station’s antenna. Sometimes the telemetry link between the field station and the recording lab experiences interference. Such noise is usually easy to distinguish from earthquake-generated signals because the noise is often “spikey” in appearance.

Blasts from local mining and quarrying operations are sometimes recorded by the seismic stations. Blasts usually occur during daylight hours, so checking the time of day may help to identify these types of sources.

Suspected blast from a mine, recorded by station BMUT.

Suspected blast from a mine, recorded by station BMUT.

Wildlife and livestock activity can be another source of noise, which is particularly common in Yellowstone and other wildlife areas. The amplitude of the signal increases as the animals approach and decreases as they leave.

View looking down from the station showing a small sample of the bison herd grazing nearby.

View looking down from the station showing a small sample of the bison herd grazing nearby.

Weather can create noise spikes caused by iced up antenna or strong winds interfere with radio telemetry.

A solar panel and antenna covered in ice that resulted in noise and eventually the station losing power as the battery was not being recharged by the ice-covered solar panel.
A solar panel and antenna covered in ice that resulted in noise and eventually the station losing power as the battery was not being recharged by the ice-covered solar panel.
Station NAIU at Antelope Island, Utah is sensitive to wind. This is several night-time hours of wind generated noise. Station ICU in Indian Springs Canyon, Utah and some of the Yellowstone National Park stations are also sensitive to wind. Telemetry noise at GZU can be caused by the buildup of ice on the station’s antenna. Sometimes the telemetry link between the field station and the recording lab experiences interference. Such noise is usually easy to distinguish from earthquake-generated signals because the noise is often “spikey” in appearance.
Station NAIU at Antelope Island, Utah is sensitive to wind. This is several night-time hours of wind generated noise. Station ICU in Indian Springs Canyon, Utah and some of the Yellowstone National Park stations are also sensitive to wind. Telemetry noise at GZU can be caused by the buildup of ice on the station’s antenna. Sometimes the telemetry link between the field station and the recording lab experiences interference. Such noise is usually easy to distinguish from earthquake-generated signals because the noise is often “spikey” in appearance.