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The importance of geotechnical effects was brought home through a series of important earthquakes between the 1960s and 1980s. These earthquakes include Southern Chile 1960, Niigata 1964, Alaska 1964, Caracas, Venezuela 1967, San Fernando, California 1971, Tangshan, China 1976, and Mexico City 1985. The earthquakes in Chile, Niigata, Alaska, San Fernando and Tangshan were especially important in providing evidence and impetus to the study of liquefaction, settlement and soil failure including effects on earth dams, while Caracas and Mexico City played a similar role with respect to site amplification and increased structural damage due to the amplification of ground shaking.
Idriss and Boulanger (2008) state: “The 1964 Niigata earthquake (MW7.5) and 1964 Alaska earthquake (MW9.2) helped to identify liquefaction as a major problem in earthquake engineering. For example, the loss of shear strength and stiffness in liquefied sands during the Niigata earthquake resulted in dramatic bearing failures beneath buildings, the floating of buried tanks, …, and the collapse of bridges.” Indeed, the bearing failures, tilting and overturning of Kawagishi-cho apartment buildings (Figure 1), the collapse of the Showa Bridge, and observations and video recording of the sinking of Niigata Airport Terminal Building are firmly established as some of the benchmark case histories in our field. Similarly, the slide of the upstream shell of the Lower San Fernando Dam during the 1971 earthquake is another such prominent case history that marked a major change in embankment dam engineering throughout the world. These benchmark case histories have been the subject of numerous research studies and grow in significance with the passage of time.
Figure 1: Rotation of Kawagishi-cho apartment blocks as a consequence of liquefaction
These 1960s and 1970s earthquakes influenced policy makers, engineers and the research community in several countries, with increased funding and re-focusing of engineering and research groups towards documenting and studying these effects, creating expanding databases of case histories and related in-depth studies that resulted in new simplified and computational engineering procedures available to practicing engineers. An important development was the quantum jump in international cooperation in all stages from database documentation to development and acceptance of these new engineering approaches and procedures. The essentially continuous collaboration between North America and Japan, starting after the Niigata earthquake, played a most significant role in this process, establishing an important precedent that continues to this day.
One development which was important in the U.S. and other countries was the need to conduct seismic studies for nuclear power plants in this time period, in parts of the country which went beyond California and other seismic areas, thus increasing national awareness of the seismic threat at a national level and propelling forward developments on issues like site amplification and especially soil-structure interaction (SSI). The introduction of the equivalent-linear solution and the computer programs SHAKE and FLUSH contributed significantly to the evaluation of seismic performance of nuclear plant structures and underlying soils.
Kenji Ishihara explained the early period of development of Earthquake Geotechnical Engineering: “After the Niigata earthquake in 1964, the delegates from US paid several visits to Niigata to investigate features of liquefaction-devastated area. After finishing the series of laboratory tests at Berkeley, Professor Seed was kind enough to give several talks in Japan concerning the causes of liquefaction. These were very stimulating and encouraging to us, the Japanese young engineers as Drs. Y. Yoshimi, H. Kishida and myself. Professor T. Mogami (1911-1986) and M. Fukuoka (1917-2015) appear in position to push young generation forward to initiate studies of liquefaction. I was put in a position to act as a liaison officer to advance cooperation between US and Japan. In 1964, just a week before the 7th ICSMFE was held in Mexico City, the US-Japan seminar on soil dynamics was held at Berkeley. Prof Mogami was the chairman on the Japanese side and Dr. Y. Iwasaki attended it. Prof. H.B. Seed and I continued to act as coordinators to continue the cooperation and we had seminars twice afterwards.
Afterwards, when the 10th ICSMGE was held in Stockholm in 1981, Prof. Seed gave the special lecture on the failure of Teton Dam. He was representative of the US national society and met with success in inviting the 11th ICSMFE to San Francisco (Figure 2). As the Secretary General K. Nash passed away suddenly a week before the Stockholm conference, it appears to me that it was Prof. H.B. Seed who proposed the institution of the ‘Kevin Nash Gold Medal’ in ISSMFE.
Sometime in 1984, I received a letter of invitation from H.B. Seed to write up and deliver a theme lecture on Stability of Natural Deposit at the time of 1985 San Francisco Conference. When I send out the draft, Prof. Seed reviewed it and kindly corrected my draft. I still keep a mind of gratitude to him for his kindness.”
Figure 2: Drs. K. Fujita, T. Akagi are shown together with Prof. H.B. Seed and Prof. K. Ishihara during the 1985 11ICSMFE
I. M. Idriss commented on the early development and activities from 1962 to 1973 in USA: "Significant advances occurred in the 1960s and early 1970s that included: use of finite element method, which had been created by Professor Raymond Clough in the late 1950s, in static and seismic analyses of soil structures (embankments, slopes etc.); modifications by Lee and Seed of the triaxial testing device and later modifications of the direct simple shear device by Peacock and Seed, to conduct cyclic tests of sand specimens that provided the means to simulate liquefaction and to assess how and what affects liquefaction in clean sands; development of the lumped-mass bilinear solution by Parmelee, Penzien, Sheffey, Thiers and Seed to evaluate seismic response of soft clays; introduction of the Newmark method for estimating seismic deformations of slopes; development of the liquefaction evaluation procedure, anchored on the liquefaction case histories from Niigata, data for which had been generously provided to us by our Japanese colleagues; development of the Seed-Idriss simplified liquefaction procedure; development of the equivalent linear procedure by Idriss and Seed for use in 1D and 2D seismic response analyses; development of the Seed-Lee-Idriss method for evaluating seismic performance of embankment dams, anchored on the Sheffield Dam failure in 1925 and refined based on the performance of the Lower and Upper San Fernando Dams in the 1971 San Fernando earthquake; correlation of building damage with local site conditions, anchored on observed damage patterns in the 1967 Caracas earthquake, by Dezfulian, Seed and Idriss at UC Berkeley and Whitman and Dobry at MIT; development of the Makdisi-Seed simplified procedure for estimating seismic deformations of embankment dams; use of the frequency-domain solution and the equivalent linear representation in 1D and 2D seismic response analyses led by Professor John Lysmer at UC Berkeley resulting in the publications of computer programs SHAKE, FLUSH (and much later SASSI) – just to mention a few key developments in this period.
The earthquakes that had the greatest influence during this period (1962 – 1973)- were: the 1964 Great Alaska (M = 9.2); 1964 Niigata (M = 7.5); 1966 Parkfield (M = 6.2); 1967 Caracas (M = 7) and the 1971 San Fernando (M = 6.6) earthquakes."
Ricardo Dobry shared: “I am also personally very aware of the importance of some strong collaborations in the 1960s and 1970s between U.S. and Chilean universities, including extended stays in Chile of Prof. Martin Duke of UCLA and Profs. Whitman and Roesset from MIT in the 1960s, and Chilean students coming also in the 1960s to study in the U.S. An important and very intense collaboration developed between a number of countries and Mexico after the 1985 earthquake aimed at clarifying and fine tuning important aspects of the site amplification phenomenon.”
Kenji Ishihara continues: “In 1963, a fairly large-scale earthquake with a magnitude 6.1 hit the area of Skopje, the capital city of North Macedonia. To help restoration of the city and to nurture experts of engineers, the Institute of Earthquake Engineering in Skopje was established with the help of UNESCO. Several experts from Japan were involved in the initial work for the installation. This was the place where Dr. M. Cubrinovski was nurtured.”
The advancement of the earthquake geotechnical engineering has been enhanced through the quadrennial International Conference on Earthquake Engineering (ICEGE), that was established by TC203 (formerly TC4) in 1995. The flow chart (Figure 3) illustrates the evolution of conference activities within TC203 including names of the chairperson of each conference and the chairperson of TC203. Another TC203 conference series was inaugurated in 2009, the International Conference on Performance-Based Design in Earthquake Geotechnical Engineering (ICPBD) which focuses specifically on problems associated with engineering practice.
Regarding the establishment of TC4, Kenji Ishihara noted: “Sometime before the San Francisco Conference, I was asked by the Japanese Geotechnical Society to take care of a technical committee dealing with soil dynamics related to earthquake engineering. I remember a small meeting was summoned by Prof. H.B. Seed in San Francisco during the ISSMFE Conference. I supposed there were I. Idriss and S. Prakash. After the San Francisco Conference in 1985, I thought it necessary to activate the technical committee and organized a small workshop-type conference in Tokyo. I still remember vividly that Dr. I. M. Idriss came kindly to Japan to activate the newly born Technical Committee No. 4. A small group was then formed in the Japanese Geotechnical Society to discuss issues of the earthquake-related geotechnics. Drs. T. Kokusho, I. Towhata S. Yasuda, S. Iai, K. Wakamatsu. J. Koseki and several others were core-members. We met frequently and eventually published two books on microzonation for liquefaction and rainfall disasters. It was very lucky to have the Japanese group who was very enthusiastic to push forward the activity of TC4.
The next opportunity to demonstrate outcome of TC4 was at the time of the 12th ICSMFE held in 1989 in Rio de Janeiro. We succeeded in organizing a small seminar on that occasion and published a booklet. It was our greatest surprise and disappointment to hear the passing away of Prof. H. Seed at a still young age of 69.”
Figure 3: TC203 major conferences, conference chairs and TC203 chairs
References
References
Idriss, I.M. & Boulanger, R.B. 2008. Soil liquefaction during earthquakes. EERI.
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