Geoscience Reference
In-Depth Information
will be responsible for oficially determining earthquake parameters. Based on the committee's
review of the warning messages, magnitude determinations included in the warning mes-
sages sometimes differ between the two TWCs. The warning message is communicated to the
National Earthquake Information Center (NEIC, see also Box 5.1) but the TWCs typically attempt
to determine the seismic location and magnitude more rapidly than NEIC. Subsequent mes-
sages from the TWCs may include corrections to the magnitude determination issued in the
irst message. Given the beneit of consistency in warning message dissemination (discussed in
Chapter 3), avoiding such inconsistencies in earthquake parameters between different warning
products would be beneicial to the warning process.
Although many of the required functions are similar, the detection procedures followed by
each of the TWCs differ and the centers use different operating systems and graphical user inter-
faces (Table 5.1). The WC/ATWC uses personal computer (PC) workstations running Microsoft
Windows and all seismic, sea level, geographic information system (GIS), forecasting, and
product-generation software run on a network of 10 operational PCs with complete hardware
and communications redundancy. Development, testing, and training operations are performed
on three other computers. In contrast, the PTWC utilizes seven redundant Sun/Solaris work-
stations, and functions are migrating to the open-source Linux operating system. The develop-
ment of incompatible hardware platforms was based on the availability of local knowledge at
each TWC, rather than on a formal information architecture development or planning process.
Each TWC uses different software for its real-time monitoring and analysis systems: the
PTWC runs Antelope
3
to manage seismic data streams. This software package is currently used
at several other earth science programs (e.g., Earthscope Array National Facility, Saudi Arabia
National Seismic Network, Alaska Seismic Network, Singapore National Telemetry Network,
Dominican Republic Seismic Network, Ocean Observatories Initiative Cyberinfrastructure com-
ponent). The WC/ATWC and the PTWC use software based on Earthworm (version 7.1), an open
source package for regional seismic networks developed by the USGS in 1993. As of 2007, 40
observatories
4
in addition to the WC/ATWC and the PTWC were using Earthworm despite the
lack of active software development or maintenance.
Because there is no common software architecture, each TWC operates with a different set
of standards and procedures. The processes followed by scientists receiving sensor information
differ and are supported by different analytical tools in each TWC. The analyses, results, mes-
sages, thresholds, and notiication processes supported by each TWC's hardware and software
technology are also therefore different, and the customer-facing software interfaces and re-
ports provided to the public and the media from each TWC differ; the result of the differences
suggests that the two TWCs are not part of the same organization, with the same mission.
The differences introduce another set of operational challenges, as, based on the committee's
observations, it appears that a scientist working at one TWC would have dificulty covering a
shift at the other TWC without signiicant additional training. Despite these differences, how-
3
http://www.brtt.com/.
4
The list was obtained from http://folkworm.ceri.memphis.edu/ew-doc/.
