O4 Seismic Channel Data Release

Data Set

This data set includes seismic channels recorded by the LIGO detectors during the O4 observing run. For context, see the O4 data release documentation.

The LIGO instrument at each site uses a large number of sensors to track the state of both the instrument and the surrounding environment.

In this page we release a specific seismic dataset over a long period (about 2.5 years) that corresponds to the O4 run, starting 2023-05-24 and ending 2025-11-25. Channels belong to 256Hz measurements of seismometers (Guralp model CMG-40T) for both Hanford and Livingston interferometers. Seismic sensors are distributed around main buildings and both arms.

Channel Names

Each channel has a name using this structure: [IFO]:[SYSTEM]-[NAME], where:

  • [IFO] is the instrument (e.g., H1 refers to LIGO Hanford)
  • [SYSTEM] is an acronym for the instrument subsystem (e.g., PEM means "Physical Environment Monitor")
  • [NAME] is a name describing the channel (often containing more acronyms).

Channel List

This data set includes 18 channels from LIGO Hanford: 

H1:PEM-EY_SEIS_VEA_FLOOR_(X,Y,Z)_DQ
H1:PEM-EX_SEIS_VEA_FLOOR_(X,Y,Z)_DQ
H1:PEM-CS_SEIS_LVEA_VERTEX_(X,Y,Z)_DQ
H1:PEM-MX_SEIS_VEA_FLOOR_(X,Y,Z)_DQ
H1:PEM-MY_SEIS_VEA_FLOOR_(X,Y,Z)_DQ
H1:PEM-VAULT_SEIS_1030X195Y_STS2_(X,Y,Z)_DQ
and 9 channels from LIGO Livingston: 

L1:PEM-EY_SEIS_VEA_FLOOR_(X,Y,Z)_DQ
L1:PEM-CS_SEIS_LVEA_VERTEX_(X,Y,Z)_DQ
L1:PEM-EX_SEIS_VEA_FLOOR_(X,Y,Z)_DQ
The data set has a total size of 1.8 TB.

Data Access

NDS2

Data may be accessed from a network data server (NDS2) using the NDS2 client or GWpy. The following code can be used to download data (substitute any channel name that is a part of this data release): 

from gwpy.timeseries import TimeSeries
data = TimeSeries.fetch('H1:PEM-MX_SEIS_VEA_FLOOR_X_DQ', start=1398980000, end=1398980010, host='nds.gwosc.org')

OSDF

This data release has frame type H1_SEIS_AR1 and L1_SEIS_AR1 and is available via OSDF allowing to select and download the data. To launch large dataset jobs on a computing cluster one can use HTCondor.

To search for public data osdf file URLs, one may use gw_data_find for a given frame and segment interval:

gw_data_find -r datafind.gwosc.org -o L -t L1_SEIS_AR1 -s 1368980000 -e 1368980010 -u osdf

Alternatively, in python code, to download OSDF url files for a given frame type and GPS segment:

import os
import requests_pelican as rp
from gwdatafind import find_urls
url = find_urls("L", "L1_SEIS_AR1", 1398980000, 1398980010, urltype='osdf', host="https://datafind.gwosc.org")
with open(os.path.basename(url[0]), mode="wb") as file:
    file.write(rp.get(url[0]).content)

Additional references

Feedback

This data release is the first of its kind. Is it useful for your research? How could it be improved? Please contact us with any feedback.

Revision History

  • Feb 28, 2026: First release