More Details About Epicentral+ Seismometer Channel Sets

You can copy and paste these channels sets into Epicentral's (for the iPad) seismogram settings panel. Displaying more than about nine channels on the iPad makes each seismogram rather small, but at times, it's nice to sample Earth's ground motions broadly.

The format is listed in the settings panel:

network code; station code; location code; channel code; plot label; ...
          [highPassCorner; lowPassCorner] (all on one line)

Each parameter is separated by a semi-colon. The network, station, location, and channel codes are defined by international agreements - the point is that they have specific values. The plot label can be any string not containing a semi-colon. The highPassCorner and lowPassCorner parameters are optional. They are filter corner frequencies in Hertz used to isolate particualr frequency components of the ground motions.

Here are the channels for a high-quality seismic station in central Pennsylvania. The horizontals are not perfectly aligned with North-South and East-West, so I add the orientation to the plot label.

IU; SSPA; 00; LHZ;Standing Stone, PA, USA - Vertical
IU; SSPA; 00; LH1; Standing Stone, PA, USA - North (N10)
IU; SSPA; 00; LH2; Standing Stone, PA, USA - East (E100)

If you want to override the default filter settings and watch the signals in two different frequency bands (one that is sensitive to nearby earthquakes and another sensitive to distant earthquakes) you can use

IU; SSPA; 00; BHZ;Standing Stone, PA, USA - Vertical; 0.5; 2
IU; SSPA; 00; BH1; Standing Stone, PA, USA - North (N10); 0.5; 2;
IU; SSPA; 00; BH2; Standing Stone, PA, USA - East (E100); 0.5; 2;
IU; SSPA; 00; LHZ;Standing Stone, PA, USA - Vertical; 0.005; 0.05
IU; SSPA; 00; LH1; Standing Stone, PA, USA - North (N10); 0.005; 0.05
IU; SSPA; 00; LH2; Standing Stone, PA, USA - East (E100); 0.005;0.05;

Note that I changed from the LH to BH channels to see the high-freuqency signals.

Usually, if you are looking at multiple stations, it's best to watch the vertical component of motion. Ground motion "noise" is usually substantially smaller on the the vertical than the horizontal components of motion.

The Central United States

A set of vertical component seismograms near the New Madrid Seismic Zone.

NM; UALR; --; BHZ; University of Arkansas, Little Rock, AR, USA; 0.5; 2
NM; PBMO; --; BHZ; Three Rivers Community College, Poplar Bluff, MO, USA; 0.5; 2
NM; PVMO; --; BHZ; UM Delta Research Portageville, MO, USA; 0.5; 2
NM; UTMT; --; BHZ; UT Martin, TN, USA; 0.5; 2
NM; SIUC; --; BHZ; UM Carbondale, IL, USA; 0.5; 2
NM; BLO; --; BHZ; UI Bloomington, IN, USA; 0.5; 2