This data repository provides all relevant raw and meta data related to the NORFOX fibre optic array. NORFOX data are to be refereced with the DOI: 10.21348/

NORFOX is an innovative site in south-east Norway to evaluate the possibilities of next-generation seismic arrays with fibre-optic Distributed Acoustic Sensing (DAS) for seismology. Additionally, fundamental research on fibre technology, including DAS and DTSS (Distributed Temperature and Strain Sensing) can be evaluated. The site is co-located with the NORES seismometer array, which allows for calibration of the DAS signal. The figure below shows the location of the NOFROX fibre  array. Additionally the 16 seismometers of the NORES array are shown as white triangles. 

NORFOX cable path


NORFOX consists of 5 arms, each approximately 1700m long. You can download the KMZ file here. The arms are curved to alleviate the effects of broad-site sensitivity of the fibre-cable. This design allows thus for a homogeneous array response function (see Näsholm et al., 2022). Note that the arms at some locations deviate form the ideal homogeneous curvature due to local topography and geology. 

Challenging topography

Each arm is equipped with two cables and two empty pipes, burried 50cm deep directly in forest soil. The empty pipes (16mm inner diameter) are buried alongside the cables for future expansion. Furthermore Arms C & E have an additional 40mm pipe.

NORFOX Trench Layout


All cables are connected to the NORSAR data facility at Stendammen, where interrogators can be housed and data transfer can be ensured.

Stendammen facility

The fibre cables have the following specifications:

  • OCC 4x standard telecom fibres (G652).
  • OFS AcoustiSense with 2x enhanced backscattered fibre and 2x standard telecom fibre. The enhnaced  At the outer end of each arm each enhanced fibre is spliced to a standard fibre to close the optical loop back to the central station.
    • Strength member: Aramid Yarn
    • Diameter: 9.5mm
    • Maximum load: 200N 
    • Minimum bend radius: 47.5cm
    • Attenuation @1550nm: <0.3db/km (standard), <0.7dB/km (enhanced)
    • Increased Rayleigh backscatter window: 1530-1565nm
      • Center wavelength: 1546nm

During construction

 Trenching   Arm C



Watch the information video of NORFOX on YouTube: