Geodynamics and Tectonics Plate Analysis based on Distributed Optical Fibre Acoustic Sensor
Lead Research Organisation:
University of Southampton
Department Name: Optoelectronics Research Centre (ORC)
Abstract
Megathrust earthquakes have long occurred repeatedly in Japan. Since 2011, an oceanic observation networks constituted by point sensors connected by optical fibres have been developed to monitor seismotectonic activities in this region. In this project we expand the seismometer capabilities by using the optical fibre network itself as a distributed seismometer providing thousands of high resolution seismic measurements aimed at clarifying the source of the very low frequency earthquakes based in the accretionary wedge between the Philippine Sea Plate and the Eurasian continent, which were discovered by the DONET stations in 2015.
After initial tesing in JAMSTEC own fiber optic cables off Toyohashi, Aichi, Japan and Hatsushima, Shizuoka, Japan, a portable unit will be manufactured and will be taken on the research vessel R/V Shinsei-maru to be connected to the 10 km fibre optic extension cables via a fibre optic cable of the shipboard remotely operated vehicle. The novel distributed seismometer will be tested in the DONET stations to produce a 3D map of seismic activity along the Nankai through and investigate possible links links with the structure of the subducting plate interface.
After initial tesing in JAMSTEC own fiber optic cables off Toyohashi, Aichi, Japan and Hatsushima, Shizuoka, Japan, a portable unit will be manufactured and will be taken on the research vessel R/V Shinsei-maru to be connected to the 10 km fibre optic extension cables via a fibre optic cable of the shipboard remotely operated vehicle. The novel distributed seismometer will be tested in the DONET stations to produce a 3D map of seismic activity along the Nankai through and investigate possible links links with the structure of the subducting plate interface.
Planned Impact
This project is a joint collaboration between the University of Southampton (UK) and the Japan Agency for Marine-earth Science and Technology (JAMSTEC), which is expected to have a wide range of impact, ranging from societal to commercial, from new scientific knowledge to providing true benefits to society at large.
A description of the different types of impact is detailed below.
1) Society
This project aims to impact society in a number of ways, that will result in major improvements in Quality of life. It could provide better understanding of seismic dynamics and improved monitoring technologies that might result in increased safety for all countries having population living in seismic prone areas. The outcome of this project might be used to improve earthquake and tsunami early warning systems, decreasing the number of fatalities and economic cost of dealing with seismic aftermath.
As for International Development, impact could also be significant. There are numerous country prone to earthquakes and related Tsunami and most of them are official development assistance (ODA) compliant; the deployment of the sensing technology developed in this project couldprovide seismic information in real time using the available telecom fibre networks.
This project might also have impact in terms of Policy, in particular regarding seismic monitoring and early warning systems, which would benefit from the waveform classification system developed here.
2) Economic
This proposal will deliver a new product: a long range distributed acoustic sensor that could find applications well beyond seismic monitoring: border security, smart motorways and railways, and intruder detection systems are jsut few examples. The advantage of our proposed system over conventional existing optical fibredetection systems is that our system will be able to fully identify the acoustic characteristics of the intruder, helping to identify not just the location, but also the type of intruder (i.e. people, animals, vehicles or other objects), or event (car collision, object falling on tarmac, damaged surface).
3) Knowledge
This proposal will provide scientific advances related to geophysics: the investigation of earthquake epicentre dynamic position and the relation between different seismic activities will be at the forefront. High-speed seismic measurements by the distributed acoustic sensor will be used to determine dynamic migration of seismic epicentre during seismic activities and create a dynamic mapping of the different types of seismic activities to the detailed seismic structure. The map of migration of seismic events in the tectonic structure could be used to assess varying stress state in the seismogenic plate interface where large earthquakes nucleates. The relation between the different seismic traces will include conventional earthquakes, low frequency tremors, slow slip events and very low frequency earthquakes.
A description of the different types of impact is detailed below.
1) Society
This project aims to impact society in a number of ways, that will result in major improvements in Quality of life. It could provide better understanding of seismic dynamics and improved monitoring technologies that might result in increased safety for all countries having population living in seismic prone areas. The outcome of this project might be used to improve earthquake and tsunami early warning systems, decreasing the number of fatalities and economic cost of dealing with seismic aftermath.
As for International Development, impact could also be significant. There are numerous country prone to earthquakes and related Tsunami and most of them are official development assistance (ODA) compliant; the deployment of the sensing technology developed in this project couldprovide seismic information in real time using the available telecom fibre networks.
This project might also have impact in terms of Policy, in particular regarding seismic monitoring and early warning systems, which would benefit from the waveform classification system developed here.
2) Economic
This proposal will deliver a new product: a long range distributed acoustic sensor that could find applications well beyond seismic monitoring: border security, smart motorways and railways, and intruder detection systems are jsut few examples. The advantage of our proposed system over conventional existing optical fibredetection systems is that our system will be able to fully identify the acoustic characteristics of the intruder, helping to identify not just the location, but also the type of intruder (i.e. people, animals, vehicles or other objects), or event (car collision, object falling on tarmac, damaged surface).
3) Knowledge
This proposal will provide scientific advances related to geophysics: the investigation of earthquake epicentre dynamic position and the relation between different seismic activities will be at the forefront. High-speed seismic measurements by the distributed acoustic sensor will be used to determine dynamic migration of seismic epicentre during seismic activities and create a dynamic mapping of the different types of seismic activities to the detailed seismic structure. The map of migration of seismic events in the tectonic structure could be used to assess varying stress state in the seismogenic plate interface where large earthquakes nucleates. The relation between the different seismic traces will include conventional earthquakes, low frequency tremors, slow slip events and very low frequency earthquakes.
Publications
Zafeiropoulou A
(2021)
Flat multi-core fibre for twist elimination in distributed curvature sensing
in Optical Fiber Technology
Van Putten LD
(2021)
Numerical Modelling of a Distributed Acoustic Sensor Based on Ultra-Low Loss-Enhanced Backscattering Fibers.
in Sensors (Basel, Switzerland)
Van Putten LD
(2019)
100-km-sensing-range single-ended distributed vibration sensor based on remotely pumped Erbium-doped fiber amplifier.
in Optics letters
Redding B
(2020)
Low-noise distributed acoustic sensing using enhanced backscattering fiber with ultra-low-loss point reflectors.
in Optics express
Milne D
(2020)
An analysis of railway track behaviour based on distributed optical fibre acoustic sensing
in Mechanical Systems and Signal Processing
Masoudi A
(2019)
Subsea Cable Condition Monitoring With Distributed Optical Fiber Vibration Sensor
in Journal of Lightwave Technology
Masoudi A
(2022)
10-cm spatial resolution distributed acoustic sensor based on an ultra low-loss enhanced backscattering fiber
in Optics Continuum
Harmon N
(2022)
Surface deployment of DAS systems: Coupling strategies and comparisons to geophone data
in Near Surface Geophysics
Description | Acoustic sensing at distances over 150km from the single access point has been demonstrated using a specialty fibre developed in Southampton and in-line amplification with remote pumping. The new fibre showed negligible attenuation and increased (x100) backscattering. The effect of underwater acoustic waves on different types of optical fibre cables has been investigated. Heavily armoured cables are not as sensitive as conventional Teflon coated telecom cables. Surprisingly, conventional telecom fibres perform as well as optical fibres with armouring specially designed to increase the acoustic coupling between underwater acoustic fields and the optical signals propagating in the fibre. Initial tests underwater show the possibility to use fibres to record sound sources. A new ruggedized portable distributed acoustic sensing system has been developed for field tests. Data compression of seismic data for transmission over the internet has been developed. The ruggedized unit recorded seismic events off the coast of Japan for several weeks. Machine learning has been used on the data collected on the East coast of Japan. A program capable to identify seismic events from noise and other acoustic sources have been developed and tested on more than 500 events. |
Exploitation Route | The use of optical fibres for seismic monitoring could be used to develop new models that could eventually help mitigating the effect of earthquakes and tsunamis on populations and economic activities in close proximity of faultlines. Machine learning applications to seismic events could simplify tsunami warning systems and make them faster. |
Sectors | Digital/Communication/Information Technologies (including Software),Environment,Transport |
Description | An enhanced backscattering fibre used in this project has been considered for commercialization to investigate underwater security and naval applications. A start-up company has been incorporated |
First Year Of Impact | 2020 |
Sector | Aerospace, Defence and Marine |
Description | Development of High speed and High Resolution Distributed Temperature Sensor for early detection of damage in composite structures |
Amount | £74,819 (GBP) |
Funding ID | PIF\R1\180053 |
Organisation | The Royal Society |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 05/2019 |
End | 04/2020 |
Description | Underwater large-area high resolution monitoring by Distributed Optical Fibre Acoustic Sensors |
Amount | £241,889 (GBP) |
Funding ID | NE/T005890/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 11/2019 |
End | 11/2021 |
Description | Naval Research Lab |
Organisation | United States Naval Research Laboratory |
Country | United States |
Sector | Public |
PI Contribution | provided an enhanced sensitivity fibre for submarine applications |
Collaborator Contribution | investigation of noise in the fibres |
Impact | NRL is investigating possible scaling up of their finding. |
Start Year | 2020 |
Description | Siemens (US) |
Organisation | Siemens AG |
Department | Siemens Power and Gas |
Country | Global |
Sector | Private |
PI Contribution | exploit our DAS system for monitoring power plants |
Collaborator Contribution | Provide knowledge about components, provide consumables. |
Impact | none, yet |
Start Year | 2021 |
Title | machine learning for seismic event classification |
Description | the software analysis data acquired by the seismic network and provide a classification of events with accuracy better than 90% |
Type Of Technology | Software |
Year Produced | 2023 |
Impact | This software saves large amounts of time for event classification and will be further improved to detect events of interest |
Company Name | SABDAH PHOTONICS LIMITED |
Description | Sabdah commercializes specialty fibres with enhanced response for distributed acoustic sensing. |
Year Established | 2019 |
Impact | None, yet. Waiting for University of Southampton RIS legal team to formalise IP licencing agreement |