List of Pre-Calculated Discrete Instrument Responses

Description

List of discrete instrument responses of 14 common seismometers for 6 common sample intervals.

Usage

1

Format

List of 14 lists (each corresponding to a different seismometer), each including 6 lists (each corresponding to a different sample interval), each containing the following elements:

Sense

Instrument passband sensitivity (V * s/m)

Knorm

Normalization constant

poles

Poles of Laplace transform of instrument response (rad/s)

np

Number of poles

zeros

Zeros of Laplace transform of instrument response (rad/s)

nz

Number of zeros

dt

Sample interval for this response (s)

fmax

Maximum frequency for which this digital response matches the true analog response of the sensor within 1%

Zpg

Zpg-class element (from package 'signal') giving the digital response of the filter in terms of its zeros and poles (in Z-transform space) and gain.

Details

Seismometers are numbered as follows:

Broadband Seismometers: 1. Streckeisen STS-1 (360 s) 2. Trillium 240 (generation 1) 3. Trillium 240 (generation 2) 4. Guralp CMG-3T 5. Streckeisen STS-2 (generation 1) 6. Streckeisen STS-2 (generation 2) 7. Streckeisen STS-2 (generation 3) 8. Trillium 120 9. Compact Trillium

Intermediate Seismometers: 10. Trillium 40 11. Guralp CMG-3ESP 12. Guralp CMG-40T (30 s) 13. Streckeisen STS-1 (20 s)

Short-period Seismometers: 14: Guralp CMG-40T (1 s)

Digital responses are provided for the following six sample intervals (in seconds): 1, 0.1, 0.05, 0.025, 0.02, 0.01.

Note

The STS-2 and Trillium 240 come in multiple generations, each with a slightly different response. For the Trillium 240, serial numbers less than 400 belong to generation 1, while serial numbers greater than or equal to 400 are in generation 2. To determine which generation an STS-2 is, see http://www.iris.edu/NRL/sensors/streckeisen/streckeisen_sts2_sensors.htm .

Many short-period instruments were intentionally omitted because their responses depend on installation-specific parameters and are therefore not completely standardized. Given that discrete responses of short-period instruments can be calculated quickly, I consider the convenience of having pre-calculated responses for these instruments to not be worth the risk of the user selecting the wrong response and getting inaccurate results.

Examples

1
2
3
# 40T, 0.01-s response:
data(DPZLIST)
DPZ = DPZLIST[[12]][[6]]