Dark Fiber & Distributed Acoustic Sensing

Wednesday, April 11th, 2018 at 6:30 PM

TI Auditorium


6:30 - 7:00 PM Networking & Refreshments
7:00 - 8:00 PM Talks
8:00 - 8:30 PM Panel Session
8:30 - 8:45 PM Speaker Appreciation & Adjournment

Chair: MP Divakar
Organizer: MP Divakar

Session Abstract:Earthquake Early Warning (EEW) systems, although a few seconds to a few minutes in advance can make a difference between life and death in many cases. Seismic shaking from an earthquake travels at about 2 miles per second, so it is possible to detect a large earthquake near its source and broadcast a warning of imminent strong shaking to more distant areas before the shaking arrives. Many countries with active seismic zones, Japan for example, have networks of precision accelerometers connected by communication systems to enable EEW. In California, ShakeAlert began sending test notifications to selected users in January 2012 and this has now expanded to many more users. DAS technologies have many other applications including monitoring of ground water levels, evaluating traffic noise, etc.

Comsoc SCV is pleased to present this seminar disseminating the latest advances in DAS and their applications.

Speaker: Dr. Jonathan Ajo-Franklin

Bio: Dr. Jonathan Ajo-Franklin is a staff scientist and leads the Geophysics Department
within the Earth and Environmental Sciences Area (EESA) at Lawrence Berkeley
National Laboratory (LBNL). He received his BA in Computer Science and History at
Rice University (1998) followed by an MS (2003) and PhD (2005) in Geophysics at
Stanford University. From 2005 to 2007 he was a postdoctoral fellow at the Earth
Resources Laboratory at MIT. Since 2007, he has led a group at LBNL, first as a
researcher (2007-2013) and since 2013 as a staff scientist. Jonathans research
focuses broadly on using geophysical techniques to understand dynamic alterations
in subsurface properties of relevance to the environmental and energy sectors. His
technological focus in the field is on novel acquisition approaches including semi-
permanent seismic sources and fiber-optic distributed acoustic sensing (DAS). He is
active in several research efforts applying timelapse seismology to geologic carbon
sequestration (GCS), geothermal energy production, and hydraulic fracturing. He
also leads projects exploring the use of large fiber optic arrays and DAS for
geotechnical, seismological, and hydrogeological monitoring at the basin scale.

Title: Telecommunication fiber-optics cables as dense seismic arraysa tale of dark fiber

Abstract: Recent advent of distributed acoustic sensing (DAS) technologies have transformed telecommunication fiber-optic cables into dense arrays of seismic sensors. As a result, dark fiber, the redundantly installed, currently unused telecommunication fiber, could be repurposed into massive seismic arrays. In this talk, Jonathan will present the latest results obtained from the Lawrence Berkeley National Laboratory's FOSSA (fiber-optics Sacramento seismic array) experiment. The experiment uses a 13-mile-long dark fiber section (part of the ESnet testbed) to record both natural earthquakes and traffic noise that are needed for near-surface seismic imaging. Despite being installed entirely for telecommunication purposes, these dark fibers are effective in recording both earthquake signals and traffic noise, hence making fiber optics a powerful enabler in seismic applications ranging from earthquake early warnings to seismic imaging of ground water levels.