GET /irisws/sacpz/1/query

iris.edu:iris-web-services

Summary: Get SAC Poles and Zeros
Operation ID: getSACPZ
Auth: none

Get instrument response in SAC Poles and Zeros format. SAC PZ is a compact text format containing just the essential components of an instrument response: poles, zeros, and normalization constants. This is simpler than the full RESP format and is often preferred when you only need the basic response information for deconvolution. Returns the poles and zeros that define the frequency response of the seismometer and digitizer system. Use this when you need instrument response information in a format that's easy to parse and directly usable with SAC and other seismic software.

Original spec description

Retrieve SAC poles and zeros instrument response information.

Usage Tips

- SAC PZ format is much simpler than RESP but contains less complete information - The response includes: poles (complex), zeros (complex), A0 normalization constant, and overall gain - Some stations return empty responses (0 bytes) if no PZ information is available - The poles and zeros define the frequency response of the instrument - Required for removing instrument response (deconvolution) in SAC software - Typically each channel has 2 zeros and multiple poles depending on the instrument type - The time parameter is required - instrument responses change over time when equipment is replaced - If you get an empty response, try a different time or check that the location code is correct

Parameters (6)

channel (string, query, optional)

Channel code

endtime (string, query, optional)

End time

location (string, query, optional)

Location code

network (string, query, optional)

Network code

starttime (string, query, optional)

Start time

station (string, query, optional)

Station code

Examples (4)

TitleTypeURLAction
Get SAC poles and zeros for a specific station and time curl https://service.iris.edu/irisws/sacpz/1/query?net=IU&sta=ANMO&cha=BHZ&loc=00&time=2023-01-01T00:00:00
Get response for regional network station curl https://service.iris.edu/irisws/sacpz/1/query?net=CI&sta=SLA&cha=HHZ&loc=--&time=2022-06-15T12:30:00
Get horizontal component response curl https://service.iris.edu/irisws/sacpz/1/query?net=US&sta=CCM&cha=BHE&loc=00&time=2021-09-01T00:00:00
Get SAC Poles and Zeros openapi-spec https://service.iris.edu/irisws/sacpz/1/query?network=IU&station=ANMO&channel=BHZ

Probe History

Latency

Status Codes

TimeStatusLatencySize
2026-03-23 10:36:00.759869 200 723ms
2026-03-23 10:20:35.666454 200 871ms
2026-03-23 09:45:47.164603 200 873ms
2026-03-23 09:05:57.101058 400 852ms

Response Changes

WhenOldNew
2026-03-23 09:45:47.164603 79889a53aa0d d9aed80c956b
2026-03-23 10:20:35.666454 d9aed80c956b e3b0c44298fc
2026-03-23 10:36:00.759869 e3b0c44298fc 1b2e4f26b9d9