Nevada Seismological Laboratory: University of Nevada, Reno Seismological Laboratory/174 Mackay School of Mines Reno, NV 89557 (775) 784-4975 Recent Earthquakes FAX: (775) 784-1833 E-mail:mainofc@seismo.unr.edu

Nevada’s Earthquake Monitoring Network Expands

Background

The University of Nevada Seismological Laboratory (NSL) has received support from the U.S. Geological Survey to set up a pilot system for real-time earthquake monitoring and automated earthquake notification. The pilot system consists of 12 new state-of-the-art instruments located principally in the Reno — Carson City urban corridor, with some of these instruments also to be installed in Las Vegas. One purpose of the new program is to collect data that will be used to produce a contour map of strong ground shaking (see Attachment 1 for an example of ShakeMap). The so-called ShakeMap will be available on the Worldwide Web within minutes of the earthquake's occurrence. Such a map would be used by emergency responders to decide where to deploy resources following a damaging earthquake. Similar prototype systems are being installed in Seattle, San Francisco, Salt Lake City, Anchorage, and Memphis. These systems are prototypes for a larger Congressional initiative, the Advanced National Seismic System, or ANSS (see Attachment 2). Should the ANSS receive full funding, the Nevada network would expand to approximately 300 stations located in the urban areas around Reno-Carson City and Las Vegas.

Phased Installation

The new earthquake recording stations will initially be installed in the urban portions of Reno, Sparks, Carson City, and Las Vegas (see map, Attachment 3) to supplement our existing network of stations in these cities. The goal is for the first 12 stations to be installed by Fall of 2001, although completion of the telemetry connections for online integration at the NSL may be delayed somewhat. ShakeMap and the automated emergency notification system will be phased in subsequently.

Technical Installation Details

The new recording network will consist of a sensor (called an accelerometer) capable of recording strong ground motions (up to 2 g) on scale. The existing NSL seismograph network generally consists of sensors designed to record weak ground motions and will not remain on-scale during even a moderate-sized earthquake. Data from the sensor will be continuously telemetered to the University of Nevada campus via either an existing Internet connection, a telephone frame-relay connection, or via a spread-spectrum radio network. The telephone/radio connections are operated entirely at our own expense. Stations will be installed within existing small buildings (typically a one-story reinforced structure less than 4000 square feet in area) or we will fabricate a small enclosure if the unit is installed away from existing structures. Regardless of the type of installation, all construction and installation work will be coordinated through personnel designated by the property owner. The complete installation will be at no expense to the property owner.

Building Installations

If installed in an existing building, the sensor and associated electronics will require an area of about 6 square feet (3’ x 2’) on a concrete floor poured directly on the ground (See Attachment 4). The unit requires AC power (110/115V AC) and should be installed in a location with access to a dedicated outlet within about 10 feet. If an A/C outlet is not available in the immediate vicinity of the instrumentation, we will contract with a licensed electrician to install a more convenient outlet. An uninteruptible power supply will provide about 140 hours of emergency power in case of electrical failure. The equipment draws a negligible amount of current (less than one amp). There is no fire hazard from this equipment.

Precise timing is provided to the instrument by a GPS clock. The GPS clock obtains a signal from orbiting satellites and therefore an antenna will need to be located on the roof of the building or otherwise external to the building. The GPS antenna will be connected to the sensor via either existing conduit or via conduit we install. Additional electronics will connect the sensor to the telemetry system. Attachment 4 is a photograph depicting the equipment to be installed.

In some cases, we will install a radio transmitter on the roof next to the GPS clock. The antenna will typically be yagi-style, approximately 2 feet long. A cable from the antenna will be connected to the sensor along the same conduit as the GPS cable. More typically, we will install (at our expense) a frame-relay telephone connection to the unit.

Free-standing Installations

In situations where a suitable building is not available, we will fabricate housing for the sensor and its electronics. The installation will consist of a small (3 feet x 3 feet) concrete pad (installed using hand tools) with a locked fiberglass weatherproof hut installed over the instrumentation and secured to the concrete pad. It may be necessary to dig a small trench in which we will place conduit containing cables connecting the sensor to a nearby power or telephone connection. In such cases, the trench will be dug using hand tools, completely buried with minimal impact to the environment.

Some of these installations may be solar powered, in which case we will install a small radio tower (maximum of 20 feet high with a 12 inch triangular base in a concrete footing). We will mount the solar panels (approximately 3 x 3 feet), a radio transmit antenna, and GPS antenna on the tower. A 3 foot diameter x 2 foot deep barrel containing l2-volt batteries will be buried in the ground adjacent to the tower.

For information about earthquakes in Nevada, please check our Website at www.seismo.unr.edu.