1. Incorporated Research Institutionsfor Seismology
https://www.surveygizmo.com/s3/4717567/CORES-Community-Input
Beyond EarthScope - What is next
for Earth Science?
2. Incorporated Research Institutionsfor Seismology
Transportable Array: A Unique
Capability for Earth science
• ~400 stations occupying 1687 sites
• ~70 km spacing
• Broadband vault seismometers
• Real-time telemetry (cellular, VSAT)
• Free and open data access
2004-2015
3. Incorporated Research Institutionsfor Seismology
Transportable Array: Alaska
• ~280 stations
• ~85 km spacing
• Broadband posthole
seismometers
• Infrasound, pressure,
meteorological and soil temp.
sensors
4. Incorporated Research Institutionsfor Seismology
New Technology for Alaska TA
Challenges
• Remote sites accessible only by helicopter
• Long, dark, cold and snowy winters
• Complex logistics
• Very limited cellular coverage for communication
New Technology
• First use of broadband, posthole seismometers
• Helicopter-transportable rock drill
• Helicopter-transportable fully-assembled station hut
• Advanced Li-Fe-PO4 batteries (16.2 kWh)
• Inmarsat BEGAN satellite telemetry for data
transmission (<1 hr)
EarthScope’s Transportable
the Last Fron er
A er covering the lower 48 United States
from coast to coast with a grid of nearly
1700 sites, the fina l se ismic sta on of the
EarthScope Transportable Array has been
installed in Alaska.
The Alaska Transportable Array (TA) is
a currently opera ng 280-sta on seismic
network that con nuously records ground
mo on from local, regional, and global
earthquakes and broadcasts its data in real
me from the last fron er. The success of
this ambi ous scien fic endeavor is largely
due to the focused efforts of a small number
of employees who have coordinated
complicated shipping schedules, obtained
diverse land use permits, and spent the past
three summers naviga ng poor weather
condi ons, fires, and wildlife across Alaska
and western Canada.
Above: Ma
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5. Incorporated Research Institutionsfor Seismology
Unique Capabilities of the TA
• Can be deployed on a regional or continental scale
• Use of multiple, professional crews working year-round
• Construction/installation and operations handled by different expert
teams
• Standardization of equipment for entire array (sensors, data loggers,
clocks, vaults, etc.)
• Streamlined process developed for station surveying, permitting, site
construction and deployment
• Novel approaches developed for sensor emplacement, power
generation, real-time data transmission and multi-sensor integration
• SOH information monitored in real-time to maintain data integrity and
quality
• Data and metadata immediately available to any interested investigator
6. Incorporated Research Institutionsfor Seismology
Examples of TA Applications
• Map size and locations of earthquakes
• Determine type of fault and rupture processes
• Investigate rupture process of great earthquakes
• Image tectonic structure on regional/continental scale
• Map crustal thickness, anisotropy and Moho depth
• Determine lithospheric thickness; depth of LAB boundary
• Detect sea-ice changes in the Arctic
• Atmospheric studies
After TA
Before TA
7. Incorporated Research Institutionsfor Seismology
Future of the TA
• No new projects comparable in scale to the EarthScope TA have
been funded in the U.S.
• Canadians are planning a project modeled after the TA in the
Canadian Cordillera (CCArray)
• TA-like projects are being carried in China
• The need for TA-like capabilities have been identified in other
international planning efforts, for example SZ4D, but no firm plans
are in place
• Should we try to retain the technical and management expertise in
the U.S. community to conduct TA-like experiments post-2020 or
should we develop other transformative new capabilities for the
Earth science community?
EarthScope had a very ambitious goal – to study the structure and evolution of the North American continent. In order to achieve this goal, IRIS develop a new capability for EarthScope, called the Transportable Array, part of the larger USArray. The TA consisted of ~400 high-quality, broadband seismometers that rolled from west to east across the US. Nearly 1700 sites, spaced about 70 km apart, were occupied during a 12 yr period from 2004 to 2015. Each site was occupied for about 2 years. The TA was augmented by “Flexible Array” experiments – much denser deployments shown in yellow here. FlexArray experiments were conducted in the Big Horns in Wyoming and on Snake River Plain.
The TA was a massive experiment on a scale never before attempted by the Earth sciences community. Each station was consisted of a vault, about 2 m tall that housed the seismometer, datalogger, and rechargable backup batteries for its solar panels. Each vault was installed using a backhoe. During the 14-years of operation, 98-100% of the stations were operating at any given time.
