The IMAGE passive seismic project on Reykjanes peninsula, Iceland

GEORG Geothermal Workshop 2016, Reykjavík

Hanna Blanck, 24.11.2016

The Network

Seismometer setup

OBS deployment

First results

DAS (distributed acoustic sensing) technology

− Passive sensor cable

− Only the fiber optic cable is subject to the temperatures in the borehole

− Higher temperature tolerance than conventional sensors

− Possible recording in > 200°C

− Simulteneous data aquisition over long distances (several km)

− Sampling with high spatial and temporal resolution

− Test of DAS method for borehole and surface seismic measurements

− 9 days of recording

− Active shots and passive recording

The measurement princible

seismic

wave

The measurement princible

laser pulse

seismic

wave

The measurement princible

laser pulse

seismic

wave

backscattered

light

The measurement princible

laser pulse

seismic

wave

backscattered

light

The measurement princible

laser pulse

seismic

wave

backscattered

light

phase shifted

Cable installation

Active recordings

- Hammer seismics

- Distance along fiber calculated from signal travel time

- hammer shots every 250 to 500 m along the surface cable

- to locate individual traces for spatial distribution

Summary/Outlook

- 2066 earthquakes recorded in 16 month

- Tomographic studies are ongoing

- DAS technology is well suited to monitor seismic signals in magmatic environments

- Focal mechanisms (ÍSOR)

- Ambient noise techniques (GFZ, TNO)

- Seismic interferometry (TNO)

Summary/Outlook

- 2066 earthquakes recorded in 16 month

- Tomographic studies are ongoing

- DAS technology is well suited to monitor seismic signals in magmatic environments

- Focal mechanisms (ÍSOR)

- Ambient noise techniques (GFZ, TNO)

- Seismic interferometry (TNO)

Questions?