Issues
Letters
LETTERS
I have been urged by colleagues to pass these comments on to you, for whatever they are worth. They regard the last SRL that included my article about the Xmap8 program and the spectacular cover figure. I have received numerous comments and requests about the article, which was nice. There has also been a marked increase in the number of researchers logging in to get the Xmap8 software. I noticed that Steve Malone's name appears above mine (in larger font) on the first page of the article, making it look like he either authored the paper or was a co-author. While I appreciate Steve's unselfish efforts in the journal, somehow this does not seem right for my article. Another oversight was the lack of an entry in the Table of Contents referencing the article with my name associated. Finally, there was some confusion regarding the relation of the cover figure...
News & Notes
NEWS & NOTES
SSA EMAIL LIST ON GOVERNMENT ACTIVITIES SSA has established an email distribution list for the Action Initiative Volunteers, a group of members who are interested in government activities that affect seismology. Any member who is concerned about events in Washington may subscribe. In a recent letter to current Action Initiative Members, Terry Wallace, Chair of the Committee on Government Affairs and SSA Vice-President, wrote: “As many of you know, the U. S. House of Representatives voted to reduce funding to the U.S. Geological Survey NERHP program by 8.7 million, effectively eliminating funding for the external grants program, which provides funding to university researchers. Thanks to the efforts of many concerned scientists, the Senate restored about $4million of the cuts and removed the restriction that the total amount of the cuts must come from university grants. The fate of the budget and the external grants program is now in the hands...
The Copala, Guerrero, Mexico Earthquake of September 14, 1995 (Mw=7.4): A Preliminary Report
INTRODUCTION The Copala, Guerrero, Mexico earthquake is the largest earthquake to occur in Mexico since the destructive 1985 events. It occurred at a time when earthquake awareness in Mexico was heightened, as the country prepared for numerous commemorative activities of the 1985 main shock, which were to occur five days later. The strong motion data from this earthquake highlights the enormous progress in instrumentation that has occurred over the past ten years. As in 1985, the accelerogram nearest the epicenter has peak values that are notably smaller than expected, and it seems to display a static offset when integrated. Indeed, accelerations on rock at all distances average below values that were expected based on previous experience in Guerrero. Table 1 lists hypocentral parameters for the earthquake. The UNAM epicenter is shown in Figure 1. All the hypocenters derived from teleseismic data are demonstrably less reliable. The UNAM hypocenter listed here...
Report on the Earthquake of September 14, 1995, in Guerrero, Mexico
On September 14, 1995, at 8:04 AM, local time (14:04, GMT), an earthquake of magnitude Ms = 7.2 (Mw = 7.3) took place in the Pacific coast of the State of Guerrero, Mexico, close to the town of Copala, with epicenter located at 16.7°N and 98.5°W. The shallow focal depth (17.5 km), the focal mechanism (thrust) and the low dip angle indicate that it is a typical earthquake of the Mexican subduction zone, in the interface between the North American and Cocos plates. Table 1 gives some basic seismological parameters, as well as some values of recorded peak ground acceleration (PGA) that might be of interest. The earthquake produced high intensities in the epicentral area, where it caused considerable damage in some villages in South Guerrero and Southwest Oaxaca. The region is sparsely populated, so only six people died, although 2,000 people remained homeless and more than 5,000 houses were...
Mexico City Seismic Alert System
INTRODUCTION The Seismic Alert System (SAS) for Mexico City has been operating as an experimental evaluation project since August, 1991. The aim of this project is to mitigate the effects of earthquakes generated in the Guerrero Gap. There is an advantage of 60 sec average for an early warning before a quake that occurs on the Guerrero coast strikes Mexico City, 320 km away. The system is designed to broadcast a universal alert for earthquakes in Guerrero above the threshold M ≥ 6, and a limited alert for earthquakes with M ≥ 5. The warning radio receivers are installed in elementary schools, commercial radio stations, offices of Civil and Mexican government agencies, universities, public services, and housing complexes. The civil authorities have backed up the project by increasing the preparedness of the people, to ensure that if an earthquake occurs people are ready to get through it safely and respond...
Preliminary Report on the 1995 Ridgecrest Earthquake Sequence in Eastern California
The Ridgecrest earthquake sequence began on 17 August 1995 with a ML 5.4 earthquake. As of October 3, 1995, the Southern California Seismic Network (SCSN) had recorded over 4,500 events in the sequence, with eight events of M ≥ 4.0. These earthquakes are occurring along the eastern edge of the Indian Wells Valley along a small stretch of the thoroughgoing Eastern California Shear Zone (ECSZ). Previous large events within the ECSZ include the 1992 (Mw 7.3) Landers earthquake sequence and the 1872 (M 7.6) Owens Valley earthquake. The only large earthquake to occur near Indian Wells Valle, was the 1946 Walker Pass (M 6.0) earthquake on an unknown fault in the Sierra Nevada mountains to the west. The ECSZ transfers some of the relative motion between the North America and Pacific Plates away from the San Andreas fault to the western Great Basin of the Basin and Range province. The...
The Kozani-Grevena (Greece) Earthquake of May 13, 1995, Ms = 6.6. Preliminary Results of a Field Multidisciplinary Survey
INTRODUCTION At 08:47 on May 13, 1995, an Ms 6.6 earthquake occurred in Northern Greece and severely damaged the region around the cities of Kozani and Grevena and neighboring villages. This earthquake is the largest for the last decade in Greece, a country which experiences the highest seismicity in western Europe. The epicenter is located in a region of very low historical seismic activity (Figure 1). The coordinates of the main shock of Kozani are 40°09.6′N and 21°40.2′E and the depth is about 8 km. The ISC seismicity catalog does not mention a single earthquake of magnitude greater than 5 within an area 100 km around, and the last destructive earthquake that affected this region occurred during February 896 and destroyed the city of Veria (Papazachos and Papazachou, 1989). This is very quiet in comparison to the other regions of the Aegean domain which, as a whole, exhibit a total...
The 1994 Southern California Network Bulletin
The Pasadena Office of the U.S. Geological Survey and the California Institute of Technology Seismology Laboratory (Caltech Seismo Lab) operate a network of more than 300 remote seismometers in southern California called the Southern California Seismic Network (SCSN). Signals from these sites are telemetered to the central processing site at the Caltech Seismo Lab in Pasadena. These signals are continuously monitored by computers that detect and record thousands of earthquakes each year. Phase arrival times for these events are picked by analysts and archived along with digital seismograms. Data acquisition, processing and archiving is achieved using the CUSP system (Dollar, 1989). These data are used to compile the SCSN Catalog of Earthquakes, a list beginning in 1932 that currently contains more than 258,000 events. This article contains selected parts from the USGS OpenFile Report entitled “Southern California Network Bulletin: January–December 1994” (Wald et al., 1995). SEISMICITY SUMMARY & STATUS OF...
The Internet - A Quick Recap of Where and How to get Seismological Information
Over the past year the “Electronic Seismologist” has reviewed various ways of obtaining seismological information from a variety of places using several different access programs over the Internet. Available information and access techniques are changing so rapidly that a list of Internet resources published in the January SRL is now terribly out of date. An Internet accessible version of this resource list, called “Seismosurfing” (found at URL: http://www.geophys.washington.edu/seismosurfing.html) is constantly being updated and was redesigned this past summer to make its use easier. A year ago there were approximately 25 institutions providing seismological information via some mechanism on the Internet. Currently there are 62 such institutions, most of which provide WWW service. While the original list was ordered by the time a resource was put onto the Internet and was divided into section by access technique, the new list is organized by geography and primarily lists World-Wide-Web (WWW) type access,...
The West-Central Minnesota Earthquake of June 5, 1993: An Opportunity to Re-examine Seismicity Near the Morris Fault
SEISMOLOGICAL NOTES
This report includes hypocenters for seismic events that occurred in January and February 1995 as published in the Preliminary Determination of Epicenters (PDE) Monthly Listing, U.S. Geological Survey, National Earthquake Information Center. It is limited to three types of events: (1) earthquakes with a magnitude of 6 or more, (2) earthquakes causing substantial damage, and (3) events of special interest. Time is given in Coordinated Universal Time (UTC), unless otherwise specified. Latitude and longitude are given to hundredths of a degree for all locations except for events at the Nevada Test Site, which are given to hundredths of a second of arc. Depths constrained to “normal” (33 km) or other assigned depths are indicated by “constrained.” Those made to agree with depth phases are marked “depth phases.” Reports followed by (GS) are taken from the PDE Monthly Listing. All reported intensities correspond to the Modified Mercalli Intensity Scale or other...
Articles
BSSA Changes Leadership and Expands Editorial Board
In June, 1995 the Editorship of the Bulletin of the Seismological Society of America was transferred from Chuck Langston at the Pennsylvania State University in State College, Pennsylvania to Michael Fehler at Los Aiamos National Laboratory in New Mexico. Susanna Alde is the new Editorial Assistant. In his three years as Editor, Chuck made significant improvements in the editorial process of BSSA and passed on a well-run journal. We thank him for all his work and for the improvements that he made in the mechanism for keeping track of manuscripts that are in review for the Bulletin. We would also like to acknowledge the contributions of Anne Cavanaugh and Kathy Langston, Editorial Assistants for Chuck, who kept track of the day-to-day operation of the journal and have helped to smooth the transition of the Editorial office from Pennsylvania to New Mexico. We would also like to thank the ongoing staff...
Book review
“Modern Global Seismology” by Thorne Lay and Terry Wallace
Seismology has made dramatic advances in the past decade. Nonetheless, there has not been a completely new seismological textbook introduced since Aki and Richards' (1980) now classic textbook. Thorne Lay and Terry Wallace have collaborated to change that and introduce this new book that will, without doubt, become the standard seismology textbook for a long time to come. It is an important contribution to the infrastructure of our science for the benefit it will provide in teaching a new generation of seismologists. The content of the book is revolutionary in three ways: 1. All seismology textbooks that presently exist tend to be separable into one of two groups: largely theoretical textbooks, and largely descriptive texts with a strong empirical orientation. In contrast, this book strikes a perfect balance between observational and theoretical topics. This is extremely important for a modern seismology course since the science has evolved in the past...
NEW BOOKS & MEDIA
NEW BOOKS & MEDIA
Report Released on Steel Structures Damaged in the Kobe, Japan Earthquake The Architectural Institute of Japan (AIJ) has released its special report, Damage to Steel Building Structures, on the 1995 Kobe (Hyogo-ken-Nanbu, or Hanskin) Earthquake. This report is a companion to, but does not duplicate, information previously published in the AIJ's Preliminary Reconnaissance Report on the Earthquake, which reported broadly on damage of all kinds in the earthquake. The Damage to Steel Building Structures report documents numerous types of steel moment frame and braced frame buildings with varying levels of damage up to and including collapse. The information is based on the AIJ detailed survey of 988 buildings. 324 high-quality color photographs depict overall views of buildings as well as close-ups of fractures, buckling and other damage. An accompanying 20-page abridged English translation includes table headings, summary information and all photo captions. Copies of the 167-page Kobe Earthquake report can...
ANNUAL MEETING
SSA '96 ANNOUNCEMENTS
Each fall I visit the hosts of our next annual meeting to review their plans and facilities. Since local members plan all of the arrangements for meetings, every SSA meeting is unique. Whether the meeting is held on campus or in a downtown convention center, the experience is much like being a guest in someone's home. Each organizing committee has new ideas for improving the annual meeting. Some are adopted by future hosts and others remain interesting local events. I was impressed with the plans and facilities for the meeting in St. Louis, April 1–3. It will be held at America's Center Convention Center, a spacious bright new facility in downtown St. Louis. Someone had told me that the downtown area of St. Louis was not a pleasant place to be—especially at night—but I did not have that experience at all. It's very easy to get there. You can board...
SSA '95 MINUTES
The 90th Annual Meeting of the Seismological Society of America was held March 22–24 on the campus of the University of Texas at El Paso. The Annual Business Meeting was held at a luncheon on March 23. Approximately 125 people attended. President Thomas H. Heaton welcomed everyone to the meeting and introduced the Head Table. He also introduced the headquarters staff and thanked outgoing directors for their service. Heaton turned the meeting over to incoming President, Steve Wesnousky who reported on actions taken during the board meeting of March 21, 1995. He stated that there would be no increase in dues for the coming year and no increase in page charge fees. Wesnousky thanked Heaton for his leadership over the past two years. He announced that Terry Wallace would serve as Vice-President for the coming year. Thanks were expressed to Lucile Jones for her hard work as chair of the...
EASTERN SECTION
Eastern Section News & Notes
THE SEISMICITY OF THE SOUTHEASTERN UNITED STATES—1994 SEUSSN Contributors* Charleston Southern University Delaware Geological Survey Georgia Institute of Technology Maryland Geological Survey Tennessee Valley Authority United States Geological Survey University of Florida University of Memphis University of North Carolina University of South Carolina Virginia Department of Mines, Minerals, and Energy Virginia Polytechnic Institute & State University Westinghouse Savannah River Company *For further information contact Matthew Sibol, SEUSSN Editor, Virginia Tech Seismological Observatory, 4044 Derring Hall, Blacksburg, VA 24061-0420; Telephone: (540) 231-4707; Email: sibol@vt.edu There were 73 earthquakes located in the Southeastern United States Seismic Network (SEUSSN) monitoring area during 1994. Of those, 58 were tectonic in nature and 15 were associated with reservoirs (Figure 1). Ten tectonic earthquakes and one reservoir shock were felt by residents. The largest earthquake in the region for 1994 was the August 6 shock located in coastal North Carolina near the town of New Bern....
MEETING CALENDAR
MEETING CALENDAR
DECEMBER, 1995 December 6–8 First Biennial National Mitigation Conference Alexandria, Virginia USA. (Federal Emergency Management Agency. Phone 800-769-3861.) December 11–15 AGU Fall Meeting San Francisco, CA. (AGU, 2000 Florida Avenue, NW, Washington, DC 20009. Phone 202-462-6900, fax 202-328-0566.) December 19–21 32nd Indian Geophysical Union Annual Convention and Meeting on Marine Geophysics Hyderabad, India. (P.R. Reddy, Indian Geophysical Union, NGRI Campus, Hyderabad - 500 007 India.) JANUARY, 1996 January 5–9 10th International Seminar on Earthquake Prognostics and Big Cities World Conference on Natural Disaster Mitigation Cairo, Egypt. (Prof. Dr. Yehia Abdel Hady, General Secretary of the Conference, Department of Geophysics, Cairo University Phone & Fax 202-2748175 or Prof. Dr. Andreas Vogel, Chairman, International Center for Earthquake Prognostics, Free University of Berlin, phone 4930-8386368, fax 4930-8311239, phone and fax 4930-2138522.) January 18–20 Seventh U.S.–Japan Workshop on Improvement of Structural Design and Construction Practices, Lessons Learned from Kobe and Northridge Kobe, Japan. (Applied...
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