FOSREM team replaced the previous FOS1 sensor with the new FOS5LL with a 15 km long fiber loop. The old one was working since July 2017 and give us a lot of data. The new FOS5LL (Long Loop) is ten times more accurate, has a long 15000 m fiber optic loop and 1.5 m diameter. It’s working in a closed-loop configuration with 1310nm light.
see movie about experiment.
Geophysical Observatory Fürstenfeldbruck
Ludwigshöhe 8, D-82256 Fürstenfeldbruck
FOSREM team is doing a part of the active seismic experiment. All groups installed above 40 sensors and sensors matrix. FOSREM installed four fibre optics sensors – two FOS3 and two FOS5.
See our devices installed in the field.
IWGoRS 5th International Working Group on Rotational Seismology Sun Moon Lake, Taiwan 2019/09/22 – 26
The 5th IWGoRS workshop will be held at the Teacher’s Hostel, Sun Moon Lake, Taiwan, from September 22-26, 2019. Institute of Earth Sciences, Academia Sinica (IES) will be the local host. The workshop will cover on all aspects of rotational seismology including (but not limited to):
- instrumentation (portable sensors, ring lasers, tilt correction, etc)
- observation of rotations (application domains, best practices)
- array seismology (gradients, strains, rotations)
- data processing, wavefield interpolation, phase separation
- earthquake physics
- volcano seismology
- ocean-bottom observations
- earthquake engineering
- seismic inverse problems
With the advance of portable rotation sensor, we expect more rotation observations will be shown in the workshop.
The FOS-5 sensor contains a complete fibre-optic Sagnac interferometer with 250 mm diameter fiber-optics loop, analog to digital conversion circuits, FPGA based digital processing unit for close-loop operation, power conversion and management parts. All of these are placed in a robust case, meeting the IP67 requirements.
This internal digital processing unit provides rotation speed (Omega) value directly in digital form. The FOS-5 has an RS-485 interface for data and USB interface for diagnostic. The connection provides data transmission and power supply from PCU over only one, standard M12 cable within the distance of 500 meters.
The 4th IWGoRS workshop were held at the Evangelische Akademie Tutzing (near Munich, Germany), June 20-23, 2016. The workshop was focus on any aspect of rotational ground motion including the recording of rotations, instrumentation, earthquake sources, non-standard rheologies, inverse problems, geodesy, earthquake engineering, long-period seismology, array-derived rotation, noise-correlation studies, ring laser technology, Earth’s rotation, problems of fundamental physics and others.
Our team has prepared one oral presentation and two-day demonstration of mobile Fosrem System in action. The presentation given by Prof. Leszek R. Jaroszewicz is avaiable here. Also Fosrem System data sheet is avaiable for download.
Our team announces that new mobile FOG sensor FOS2/3 is ready for operation. We have done several tests, simulating different types of earthquakes and standard waves.
It’s a mobile, fiber-optic system, based on Sagnac interferometer for monitoring rotational events and phenomena. The sensor device is optimized for measurement of the rotational rate with sensitivity equal to 2*10E-8 rad/s/Hz in pass band from DC to 327,68 Hz. The above mentioned sensitivity as well as rotation rate dynamic range up to 10 rad/s covers weak as well as strong rotational motions connected with irregular object movements, occurring during strong winds, tectonic moves and earthquakes. In this way, the developed system is dedicated to monitoring the rotational vibration in such objects as wind power plants, tall irregular buildings, bridges, and unstable grounds as well as rotational events connected with earthquakes.
The data sheet is avaiable here.