The Nevada Seismological Laboratory (NSL) has been developing relationships with organizations interested in seismic hazard and geophysical issues under the Nevada Seismic Research Affiliates (NSRA). Through NSRA groups can directly support NSL in the development of capabilities that address earthquake hazard issues in the region. One of NSRA's missions involves enhancing the capabilities of seismic monitoringand earthquake notification and response. These enhancements have in the past been assumed to be included in NSL's federal funding to maintain the regional seismic network. The significant Advanced National Seismic System (ANSS) funding initiative is due in 2001 for networks funded by the US Geological Survey (USGS). To this point, however, USGS funding for NSL has not kept up with the requirements of basic seismic monitoring for the citizens of Nevada and eastern California.
NSL staffing, computer systems and the software to maintain, manage, and analyze the increasingly large volumes of quality digital data flowing into the Nevada Seismic Network do not meet requirements for earthquake reporting and public response established by the ANSS initiative. USGS funding cannot meet these needs. As a result, some short-falls in the capabilities at NSL to meet public response requirements are unfortunately a reality in our network operations. If aspects of data analysis, public response, and quality research do not keep pace with the quality of the data, our ability to provide the highest quality and most accurate public response information will not be met. These short-falls will most likely become apparent in the aftermath of a large damaging earthquake when demand for information from NSL will be greatest.
NSRA, through its organization, can potentially provide for some of the resources to meets these needs. It should be kept in mind the NSRA may not be for every potential user of NSL data, information and other products, but can be an avenue for private sector and public groups to participate in earthquake mitigation in Nevada. Included in the discussion below are rough estimates of costs for several proposed tasks to be completed in NSRA efforts.
Recent long base line GPS measurements (Thatcher, 1999) show that as much as 6 mm/year of the plate boundary motion is directed through the Sierra Nevada - Great Basin boundary region along Highway 80 through the Lake Tahoe area. The direct relationship between these initial regional GPS strain measurements and the local earthquake hazard is not understood. Recent fault mapping in the Lake Tahoe area using high-resolution bathymetry data suggests several M 7 Holocene earthquakes in the Tahoe basin. Confirmation of the initial studies has been underway at the Nevada Seismological Laboratory under NSF support. These activity rates would be consistent with studies of the Genoa fault zone, a similar system to that in the Lake Tahoe area, that also show as many as three Holocene events.
The NSL monitors the earthquake activity for most of the Eastern California-Nevada border region from Death Valley in the south through the Lake Tahoe--Truckee and Mohawk Valley--Quincy areas to the north. Except for potential volcanic related earthquake sources in the Long Valley Caldera near Mammoth Lakes, California, NSL is the primary source of earthquake information for the California-Nevada border region. Although NSL maintains many of the Mammoth Lakes area seismograph stations for the USGS and records earthquakes throughout the Mammoth area, the USGS is the primary source for evaluating the volcanic hazard of the Long Valley Caldera area.
NSL operates a growing network of about 70 channels of analog instruments (1970's technology) and about 120 channels of high-dynamic-range 3-component digital instruments throughout Nevada and eastern California. The data from these stations are telemetered via microwave and VHF radio to the NSL in Reno and organized for event detection and processing on the Lab's computer systems. The regional seismograph network has been installed and operated by NSL with support from the State of Nevada, the USGS, the Department of Energy (southern Nevada network), the Keck Foundation, Bechtel Nevada and the Union Pacific Foundation. We also receive and share data for a number of stations of the US National Seismic Network and from seismic networks adjacent to the NSL network. Over the past year we have begun sharing a number of data channels with adjacent networks. We now receive about 100 channels of additional waveform data from the National Seismic Network (NSN), Utah, Caltech, Berkeley, and UC San Diego.
Four new stations have been installed in 1999 along the Mohawk Valley fault zone in northeastern California in order to monitor this poorly understood region of the western Basin and Range--Sierran transition zone. This effort has extended our capability to determine earthquake locations further into northern California.
To better understand earthquake occurrence in the Las Vegas area, we are installing two new state-of-the-art digital stations there, and are awaiting a BLM permit to install a third. Our abilities to detect, locate, and characterize earthquakes in Las Vegas will improve dramatically during the year 2000.
With private and federal funds we are also embarking on a new program to place instruments able to measure strong earthquake shaking in Nevada urban areas, when strong earthquakes occur. During 2000 we placed seven such instruments in the Reno and Carson City urban areas. We expect to begin installing strong-motion instruments in Las Vegas as soon as equipment funds are available.
At the start of the year 2000 the NSL converted to the Antelope Seismic Processing software (a product of Boulder Real Time Technology), and we were able to end our dependence on 1980's computer technology. Antelope provides the capability to merge both our analog and digital data under one database management system for: 1) near real-time analysis of earthquake data; and 2) more effective management of high-quality digital data for scientific research. Real-time notification processes, for both accurate locations and magnitudes, are currently being refined at NSL and other regional seismic networks. In 2000 we began to compute true local magnitudes based on state-of-the-art digital station amplitudes, avoiding the non-standard duration magnitudes we used previously.
The Antelope system provides output for both email notification and paging notification of significant earthquakes. NSL staff are also available via cellular phone 24 hours a day for confirmation of significant earthquakes from qualified parties responsible for emergency management and emergency response. Antelope provides robust capabilities for exchanging both waveform data and phase arrival time information with other networks in near-real time.
The NSL has been conducting experiments with rapid event notification via the Internet since 1995, serving an NSL version of automatic event locations (NBE-Nevada Broadcast of Earthquakes) and analyst-reviewed locations via email, fax, and the CNSS "finger" routine. Two years ago we improved the public access to these data by posting automatically-generated event maps on our web site. Our NBE event maps are updated every five minutes, and reviewed-event maps are updated every 30 minutes. Our records from these years show that the NBE maps are reliable and timely. We have recently implemented a USGS notification system called QDDS, which shares and updates notifications among all the adjacent networks. Antelope and our Nevada Broadcast of Earthquakes now produce notices in all the REDI/CUBE, QDDS, email, and Web broadcast formats.
Recent integration with REDI-CUBE in California through UC Berkeley has allowed that notification product to extend its coverage east of the Sierra crest. CalTrans has joined the NSRA effort to make this possible. CalTrans is now receiving REDI/CUBE service for this area through their existing communications with the UC Berkeley Seismological Lab, to which we send event information via the Internet.
There is also the concern that smaller earthquakes may cause rock falls in the steep terrain of the eastern Sierra and could pose a threat to road and rail traffic along major and remote transportation corridors. Small events at the M 4 to 5 level could potentially initiate dangerous rock falls. New NSL stations in the northern Sierra are critical for constraining the locations of such earthquakes, and NSL can rapidly notify NSRA members of their occurrence. We expect reliability and timeliness to improve further as we adapt QDDS to the Antelope environment and install more seismograph stations in the Sierra and Las Vegas areas.
Throughout contracted monitoring periods, NSL seismologists will provide NSRA members regular semi-annual briefing on our progress, recent earthquake activity, and earthquake hazard mitigation strategies in the California-Nevada border region. NSL staff will also be available continuously for consultation on earthquake hazard related issues.
Specific tasks required:
CalTrans through UC Berkeley has provided a portion of these costs, at a rate of $10,000 per year.
Testing and improvement of real-time notification software through Antelope system and integration of waveform and phase data with QDDS/REDI-CUBE: $20,000 (one-time) Software support for specific Antelope modules for notification, response and reporting. $15,000 yearly Supplemental network maintenance support, for existing stations: $15,000 yearly Network seismologist to operate and maintain notification systems: $15,000 yearly Paging and remote communications support for NSL personnel: $ 1,000 yearly Computer upgrades and hardware maintenance for Antelope system: $ 4,000 yearly Travel for semi-annual briefings, phone costs of consultations, meetings with facility operators: $ 1,000 yearly Yearly publication to NSRA on development of response capabilities and mitigation strategies $ 2,000 yearly Administrative support for project (1/6 time) $ 5,000 yearly
Specific tasks required:
Installation of 5 broadband and 5 strong-motion seismic stations at poorly-covered sites, with telemetry and permitting: $125,000 (one-time) Computer hardware and software for mirroring other regional data centers: $10,000 (one-time) Supplemental network maintenance support, for new stations (stations and microwave): $15,000 yearly Partial funding for network seismologist to operate and maintain mirroring and integration: $30,000 yearly Computer system administration (1/6 time) $10,000 yearly Computer maintenance and upgrades for mirroring: $ 2,000 yearly Administrative support for project (1/6 time) $ 5,000 yearly
This would involve extending Trinet's products in two ways. First, we have collected hundreds of earthquake felt reports from the public over the past four years. After a significant earthquake in our area, a dozen or more felt reports will arrive within a few minutes, often before the NBE notification. We will fully integrate our felt reporting system with the USGS's Community Internet Intensity Map (CIIM) system, which analyzes received reports in real-time for Mercalli intensity information, and corrects a continuously updated shaking map against the accumulated reports. We will work with Trinet and CIIM to further integrate the CIIM with the Shake Maps. We expect the updates to drastically improve shaking estimates in areas not well-covered by seismic stations. Poor coverage is a problem with Trinet products even in southern California.
Specific tasks required:
Computer hardware and software extending NSL's on-line seismogram data archive, for research into ground-shaking modeling for rapid response: $10,000 (one-time) Developing response capability for ground shaking maps, refining software: $ 5,000 yearly Computer maintenance and upgrades for ground-shaking map server: $ 2,000 yearly Computer maintenance and upgrades for seismogram archive: $ 4,400 yearly Computer system administration (1/6 time) $ 9,000 yearly Research seismologist to correlate instrumental and observed intensities (3/4 time, w/ benefits) $60,000 yearly Administrative support for project (1/6 time) $ 5,000 yearly
Specific tasks required:
Research seismologist to develop sensitive site notification (1/4 time, w/ benefits) $20,000 yearly Travel for semi-annual briefings, phone costs of consultations, meetings with facility operators: $ 1,000 yearly