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Communicating the scientific findings of the USGS and applying those findings to meaningful seismic-hazards reduction are multifaceted and long-term efforts. Com-municating the results ranges, for example, from providing raw data to researchers via the Internet to distributing highly interpreted seismic concepts to the general public. Applying the lessons learned from the earthquake ranges from changing laws and building codes to initiating long-term research and instrumentation programs in anticipation of future events. Some of these activities can be systematically planned and executed; others are highly experimental and must rely on ad hoc decisions and windows of opportunity for successful implementation. The USGS, however, has anticipated many communication and application needs of society, and has practiced and established its role in this regard since the inception of the National Earthquake Hazards Reduction Program (NEHRP) in 1977. The evolution of this role to date is partly encapsulated in this section through several examples of current communication and application techniques used by the USGS.
This report is part of a multimedia approach for reporting USGS findings on the Northridge earthquake. The USGS processed in parallel (1) this printed document, (2) a replication of this document in electronic format, and (3) a hyperlinked Hypertext Markup Language (HTML) tour of USGS and related findings beginning at the Northridge Earthquake Home Page on the World Wide Web (WWW) (see p. 8). This multiphased, interconnected approach serves many functions which allow for a variety of views and levels of detail for readers with widely disparate interests and levels of scientific understanding.
The electronic copy of this report is contained in several Adobe Portable Document Format (PDF) files. These files contain all text and illustrations seen in the printed report, and may be downloaded and printed using commonly accessible Internet protocols as well as viewed using Adobe Acrobat reader software. The PDF files are readily accessible through links from the Northridge Earthquake Home Page on the WWW.
The HTML tour of the Northridge earthquake investigations and findings is based on the outline of the printed report, yet the tour is not a linear process. An investigator may immediately link into any chapter or topical area from the Northridge Earthquake Home Page. The HTML tour also provides links to scientific documents such as articles for scientific journals, reference lists, fact sheets, and other materials that formed the basis for this project. Additionally, the HTML tour provides many links to earthquake-related topics beyond the scope of the Northridge earthquake project. The HTML tour is a “living” entity that will be updated and modified continually by the USGS as new information becomes available, or as obsolete materials are deleted.
|Access this report via the WWW at: http://geohazards.cr.usgs.gov|
A major function of the USGS is to provide earthquake information quickly to other government agencies, emergency response organizations, utility companies, transportation entities, and others immediately affected by earthquakes. The USGS and Caltech have substantially improved seismic recording in southern California, and they have developed a program for continuing to upgrade the system to improve its reliability and speed of data transmission.
Specific goals of the instrumentation program are:
The instrumentation program received startup funding through the NEHRP agreement (see p.4). Other funding sources include Pacific Bell Telephone for assistance in developing a telemetry system; the California OES through a proposal by Caltech and the CDMG; the NSF through a proposal by Caltech, and private funds raised by Caltech.
A USGS scientist kneels beside a portable seismograph station during the Northridge earthquake aftershock study. The site is a parking lot in front of the collapsed parking garage at California State University, Northridge.
A consortium of agencies (SCEC, USGS, and NASA) is currently installing a network of continuously recording Global Positioning System (GPS) instruments throughout southern California. The network, named the Southern California Integrated GPS Network (SCIGN), provides rapid, continuous measurements of ground deformation. As of April 1996, 38 stations were established, and there are plans for 30 more to be placed by the end of the year. Data have been collected from several stations that began operation in late summer 1994, and so far data quality has been excellent. The data are processed at the Scripps Orbit and Permanent Array Center (SOPAC) in La Jolla and the Jet Propulsion Laboratory (JPL) in Pasadena primarily through funding by the USGS, NSF, and NASA. .
Continuously recorded GPS data have provided a new baseline for studying compression of the Earth’s crust across southern California. Displacements due to compression may prove to be indicators of stress accumulation on blind thrust faults similar to the fault that ruptured in the Northridge earthquake.
Continuous GPS Monitoring All of the current and archived GPS raw data from the network are available through several anonymous FTP (file-transfer protocol) sites on the Internet (see p. 8). The most recent results of the continuously operating GPS array are analyzed by the USGS and researchers at SOPAC and JPL.
|GPS results may be viewed on any of several sites on the WWW that may be accessed through the following Uniform Resource Locator (URL): http://scec/gps.caltech.edu/scign.html|
Scientists and engineers from the USGS and other institutions and agencies aided emergency managers by preparing a shaking-intensity map for the Los Angeles area (see p. 55). This map showed estimated severity of shaking and the levels of damage likely associated with such shaking. This map was available long before a complete picture of the damage could be assembled, and it enabled emergency managers to promptly locate the hardest hit areas and to send appropriate help. The shaking-intensity map was the first use of such a map to help focus relief efforts during a disaster.
To quickly prepare accurate shaking-intensity maps after an earthquake, essential information about the location, size, and nature of the earthquake was compiled. A comprehensive broadcast system for reporting this essential information was established in 1991 in southern California. The broadcast system, called CUBE, automatically reports earthquakes recorded by the 350-station southern California seismograph network operated by the USGS and Caltech. (A companion seismograph network and broadcast system reports earthquakes in northern California; similar networks are located in other earthquake-prone areas of the United States.)
Whenever a sizable earthquake strikes, designated scientists are notified via telephone pager. Subscribers to the CUBE system, such as railroad companies, utility companies, and television stations, are also simultaneously notified. Instead of a telephone number, the location, size, depth, and other information about the earthquake scroll across the pager display. This information is fed into a computer-modeling system that incorporates geological conditions of an area. Scientists use the modeling system to calculate the shaking intensity for different locales within a large area surrounding the earthquake’s epicenter. Thus, rapid, reliable information from seismograph networks, until recently used primarily for research, is proving its value during earthquake disaster-relief operations.
These are the basic elements of the broadcast system that transmits information about earthquakes in southern and northern California. Energy from earthquakes is recorded at numerous field stations on instruments called seismographs. These seismic signals are relayed nearly instantaneously from this seismograph network to analysis centers at Caltech in Pasadena and at the USGS in Menlo Park. From these centers, earthquake information including time, location, and magnitude is relayed to designated scientists and to system subscribers via pager within 1 or 2 minutes of an earthquake. The information can also be displayed as a map on a personal computer.
During 1994-96, the USGS produced several specialty documents related to the Northridge earthquake. These included two issues of the USGS magazine Earthquakes & Volcanoes devoted entirely to early findings about the earthquake, and several fact sheets in the series Reducing Earthquake Losses Throughout the United States. Printed copies of Earthquakes & Volcanoes, v. 25, nos. 1-2, 1994, and the fact sheet series (1995-96) may be obtained from the USGS using the following contact:
|The fact sheet series is also available on the WWW at the following URL:
The USGS actively supports and collaborates with SCEC (see p. 7) in its scientific and knowledge-transfer functions through membership on SCEC’s Board of Directors. SCEC’s Knowledge Transfer Program, funded by the Federal Emergency Management Agency (FEMA), targets end users—the people and entities who make ultimate use of scientific data and interpretations. Specifically, these include disaster preparedness officials, practicing engineering design professionals, policy makers, southern California business communities and industries, local, State and Federal government agencies, the media, and the general public. Knowledge-transfer activities consist of forums and workshops, discussions among groups of end users and scientists, documenting and publishing these interactions, and developing products compatible with user needs. In 1994, the SCEC Board of Directors endorsed the concept for a Research Utilization Planning Process that focused on full scientific participation throughout the process and in implementing the plan. The process distinguished the end users that should be targeted for product development from the end users who need information, but not in the form of specialty products. SCEC is now working toward producing several reports for specific end-user groups such as property and casualty insurance underwriters, civil and structural engineers, engineering geologists, urban planners, and the general public. Examples of collaborative knowledge transfer between the USGS and SCEC include the handbook Putting Down Roots in Earthquake Country (described below), and the Los Angeles Region Seismic Experiment (LARSE) (see p.19). The very nature and contents of these two ventures—one for the general public, one for scientific researchers—clearly illustrates the breadth of communications achievable by the USGS and its collaborators.
|“Putting Down Roots in Earthquake County” can be inspected on the WWW at:
Results from The Los Angeles Region Seismic Experiment (LARSE) are frequently updated on the WWW at:
Part of the USGS effort to reach out to citizens is a 32-page personal handbook that was distributed through public libraries in southern California in October 1995. This handbook encourages earthquake awareness and preparedness by helping people understand the hazards we all face and what can be done about them. Many people in southern California and elsewhere do not take measures to prepare themselves for earthquakes for a variety of reasons, including fear, denial, and ignorance. We avoid thinking about the things that frighten us; we deny that rare events will affect us; and in many cases, we simply do not know what we can do to help ourselves. The new handbook Putting Down Roots in Earthquake Country speaks to our fear, denial, and ignorance in three parts:
The handbook is a clearly written, profusely illustrated document carefully designed for easy reading and frequent reference. The many practical aspects of the handbook include an outline for an eight-step family earthquake plan and suggestions for training family members in earthquake safety.
The handbook was prepared and brought to southern Californians by the USGS, the National Science Foundation Southern California Earthquake Center, the California Governor’s Office of Emergency Services, the Federal Emergency Management Agency, the American Red Cross, and other concerned businesses and organizations of southern California. Two million copies of the handbook were distributed in October 1995 to schools, companies, and the public through public libraries and the SCEC Knowledge Transfer Office.
“We would all be better prepared for earthquakes if we knew when the next one was coming. However, unlike the storm front that must travel to you before rain can begin, there are no warning signs for earthquakes. We have found no scientifically verifiable way to predict earthquakes.”
“Even though we cannot predict the time of the next earthquake, science can help us live safely with earthquakes. The road to earthquake safety follows several steps. First, we must estimate what earthquakes of what size are likely to occur (geology). Given that earthquake, we then estimate what the shaking will be (seismology). Given that shaking, we estimate the response of different types of buildings (earthquake engineering). Only with all these steps completed can we take the steps as a society to enact building codes and retrofitting programs to make our community safer.”
The State of California, through its Seismic Safety Commission, began a series of 5-year plans for the California Earthquake Hazards Reduction Program in 1986. The report California at Risk details the plans and is updated annually to reflect new information and changing needs. The USGS contributes to the State program through membership on and liaison to the California Seismic Safety Commission, through participating regularly in updating the State report and by membership on FEMA’s post-disaster assessment teams whose recommendations are incorporated into State plans. As part of the response to the Northridge earthquake, the USGS participated on an interagency team that developed the 1994 post-earthquake update to California at Risk. This update, originally published separately as a 1994 Status Report will be fully integrated into the State Plan in late 1996. California at Risk is an excellent example of the link between scientific findings and applying those findings to earthquake-hazards reduction through updating building codes and changing and enacting legislation.
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