These two, fairly-recently published, text books [Structural Dynamics ; Tsunamis] arrived at the NISEE library in Berkeley this summer and drew our attention.
Every four years, an ASCE Committee of civil engineers provides a comprehensive assessment of the conditions and needs of the nation’s current major infrastructure – aviation, bridges, dams, drinking water, energy, hazardous waste, inland waterways, levees, ports, public parks and recreation, rail, roads, schools, solid waste, transit, wastewater – in a report called, “ASCE’s Report Card for America’s Infrastructure (Report Card).” The comprehensive grade for the U.S. infrastructure in July, 2013 is a near-failing, D+. ASCE estimates the level of investment needed by 2020 to reverse the decline and remedy the near failing infrastructure grade is US$ 3.6 trillion.
Although the impressive scale of this infrastructure assessment recalls a 1997 remark by MIT professor and social critic Noam Chomsky that “Propaganda is to a democracy what the bludgeon is to a totalitarian state.” [See: Media Control], a wider public works context for the report can perhaps be assembled by reviewing the situation of the San Francisco – Oakland Bay Bridge (SF-OBB) in California.
During the great U.S. depression, severe unemployment was eventually combated through public works, which is why many U.S. bridges were built in the 1930s, including the original SF–OBB. Groundbreaking for this bridge took place on July 9, 1933 when construction began on the longest bridge in the world at that time. It took three years and five months to complete the “Bay Bridge”. The final bridge cost was approximately $77 million, $6 million under the estimated 1933 cost. More than 8,300 men worked on the original Bay Bridge (there were a total of 28 fatalities during the construction). In the 1989 Loma Prieta, California earthquake (M=7.09), shaking damage to the entire bridge prompted a public decision to retrofit the SF-OBB West Span double suspension bridges and to construct a replacement of the SF-OBB East Span that would include the world’s longest, Self-Anchored Suspension Span. The new, SF-OBB East Span construction which must address difficult seismic requirements ( See: Ground Motion Study) has been plagued with controversy, cost over-runs, materials problems, and delays. The replacement bridge is scheduled for completion in late 2013 although this may be delayed again. The 4 km East Span carries approximately 280,000 vehicles each day. The replacement bridge is now estimated to cost at least US$ 6.3 billion – making it one of the largest public works projects in U.S. history.
Remarkably the 2013 ASCE infrastructure report card assigns a C+ score to the ‘bridges’ category while noting that one in nine of the nation’s bridges are rated as structurally deficient and the average age of the nation’s 607,380 bridges is currently 42 years. [In earthquake engineering, bridges and other infrastructure are normally designated as "lifelines" and have assumed a sub-discipline of civil engineering where issues of infrastructure maintenance, strengthening, renewal and retrofit are commonly addressed.] But, learning from the SF-OBB East Span replacement experiences, how can massive, national infrastructure renewal be financed effectively?
As part of a national economic recovery from the world financial crisis and possibly creating significant domestic employment, one alternative, a federal, National Infrastructure Bank is actively under consideration — including differently funded financial mechanisms (see: Galston and Davis, Brookings Institute for one alternative scheme; and a no-federal funds alternative scheme proposed by Congressman John Delaney) to support investment in new or existing national infrastructure.
In late May, 2013, PEER’s NGA-West2 project, the second and final phase of the Next Generation Attenuation relationships for shallow crustal earthquakes in active tectonic regions (Western U.S.A.), released a series of reports of its work in developing Ground Motion Prediction Equations (GMPE). Updated and expanded GMPE procedures (from the original 2008 models) are available, data files used in various research components of NGA-West2 are documented (See: Timothy D. Ancheta et al, PEER-2013/03), and the earthquake ground motion data have been made public as the NGA-West2 database “flat files”.
|The NGA-West2 project database expands on the current PEER NGA ground-motion database to include worldwide ground-motion data recorded from shallow crustal earthquakes in active tectonic regions, post-2003. Events are considered shallow crustal if they occur within the continental lithosphere. The region used to collect shallow events is considered “tectonically active” if the earthquake is not located in a stable continental region (SCR), within a subducting slab or on the interface between the slab and the continental lithosphere; typically these events are near a plate boundary. Additionally, events were not excluded if they occurred in close proximity (time and space) with a previous event.|
The new data set comprised 21,539 recordings obtained during earthquakes with magnitudes ranging from 3 to 7.9, recorded at distances ranging from 0.2 km to over 300 km, and for recording stations with Vs30 (time-averaged shear-wave velocity in the top 30 m at the recording sites) ranging from 100 to 2000 m/sec. These data spanned the larger magnitude range (M = 4.5 to 7.9) and the small magnitude range. Thousands of ground motions recorded from small-to-moderate magnitude (with M = 3 to 5.5) events in California were also added. The new database includes uniformly processed time series as well as response spectral ordinates for 111 periods ranging from 0.01 to 20 sec and with 11 different damping ratios.
The quality of the strong motion database and of the subsets selected for closer study by each GMPE model team are critical for wider application of the NGA-West2 GMPE. (See: Iztok Peruš and Peter Fajfar. How Reliable are the Ground Motion Prediction Equations? SMiRT 20 – August 2009; for discussion of some other key issues for wider application). The recent history of earthquake ground motion prediction models has been well documented by John Douglas (See: ESEE 01-1 A comprehensive worldwide summary of strong-motion attenuation relationships for peak ground acceleration and spectral ordinates (1969 to 2000); BRGM/RP-56187-FR Further errata of and additions to ‘Ground motion estimation equations 1964 – 2003′ – final report and PEER-2011/102/Ground-motion prediction equations 1964 – 2010.
|A U.S. federal agency, NOAA’s National Climatic Data Center (NCDC), recently released the 2012 Billion Dollar Weather and Climate Disasters Information Report, indicating that the cost of damages across the USA in 2012 from climate and weather natural disasters exceeded US$110 billion, the second costliest year for natural disasters since 1980 — after 2005, the year of Hurrican Katrina. No earthquake losses are among the damage costs for 2012.|
Internationally, Munich Re reported 905 significant, natural hazard loss (catastrophe) events worldwide in 2012 with total losses reaching US$170 billion. Only one earthquake event, the May, 2012 Emilia-Romagna earthquakes in Italy (Mw=5.8), is included among the largest loss events of 2012 – with losses of US$16 billion (compared to Hurricane Sandy losses of approximately US$65 billion in the same year).
Despite under-representation in 2012 natural catastrophe loss figures, the largest natural disaster losses since 1980 are earthquake-related; the Great East Japan Earthquake and Tsunami of 2011 (Tohoku, Mw=9.0) where immediate losses reached US$210 billion leads the MunichRe list. A U.S. Congressional Research report (Japan’s 2011 earthquake and tsunami : economic effects and implications for the United States, that examined possible loss estimates of cascading damage from the Fukushima Daiichi Nuclear Power Station accidents, suggests “physical damage has been estimated from US$250 billion to as much as US$309 billion, the latter figure being nearly four times as much as Hurricane Katrina (US$81 billion) and roughly equivalent to the GDP of Greece and twice that of New Zealand…” and considerably larger than MunichRe estimates.
Although economic losses at this enormous scale of disaster may be difficult to infer precisely, as noted in a previous NISEE post, – “Are earthquake disasters getting worse?” – economists Fabian Barthel and Eric Neumayer have observed that “the accumulation of wealth in disaster-prone areas is and will always remain by far the most important driver of future economic disaster damage.”
In terms of human fatalities, natural disasters in 2012 produced 9,600 fatalities. Modest in comparison with the recent 2010 Haiti earthquake (Mw=7.0) that resulted in over 225,000 fatalities, the 2004 Banda Aceh, Indonesia earthquake (Mw=9.1) and the wide tsunami that followed which combined for at least 220,000 mortalities across Asia, and the 2008, Sichuan, China earthquake (Mw=7.9) with approximately 84,000 fatalities, according to MunichRe.
The risk from natural disaster in the USA remains considerable. In 2010, Robert Roy Britt an editor at ‘livescience.com’ generated a list of top 10 natural disaster worries (hazards) of scientists in the USA… on the list was a hurricane hitting New York City as well as threats posed by storms and heat waves. However, at least six of the ten ‘top’ items were related to the risk of large earthquakes and tsunamis causing massive damage and loss of life in different regions of the USA.
On March 27, 1964, at 5:36 p.m. in the Prince William Sound region of Alaska, a great earthquake (Mw=9.2 USGS) occurred on a thrust fault, a subduction zone, where the Pacific plate plunges underneath the North American plate. The epicenter was located about 120 km east of Anchorage at a depth of approximately 25 km. This earthquake was the second largest earthquake ever recorded in the world. The duration of rupture lasted approximately 4 minutes (240 seconds). Thousands of aftershocks were recorded in the months following the mainshock, many with magnitudes greater than Mw=6.0. Low population densities and the time of day on a holiday (it was Good Friday in the Christian calendar) may have prevented larger casualties. Much of the damage and most of the lives lost (131 deaths including 12 deaths in Crescent City, Northern California) were due to the effects of a large, open-ocean, tsunami and large, local wave run-ups generated by underwater landslides. Surface landslides and soil liquefaction caused extensive and significant property damage throughout the area.
The earthquake provoked an enormous federal government response for recovery and reconstruction that included a detailed, scientific investigation into the earthquake – National Academy of Sciences (1972). The Great Alaska Earthquake of 1964. National Academies Press, Washington, D.C. – published in eight volumes by the U.S. National Academy of Sciences in 1972. Numerous other investigations by industry groups (e.g.: American Iron and Steel Institute – AISI), by academics (e.g. Harry B. Seed, UCB), by insurance interests (e.g. National Board of Fire Underwriters) were also published. Today the Anchorage museum maintains an exhibit on the 1964 earthquake and tsunami events.
We recently recovered and partially restored the six photographs reproduced here from a damaged box of files donated to NISEE by the late David Leeds from his Anchorage, Alaska engineering seismology investigations in 1964. While Leeds is apparently not exclusively the photographer – (see; Stephenson, J.M. “Earthquake damage to Anchorage area utilities – March 1964” Port Hueneme, Calif. : U.S. Naval Civil Engineering Laboratory, 1964-06-24 for one photographic source) – the black & white photographs are starkly powerful representations of the great earthquake. Among Leeds’ photographic records of the event are the two photographs reproduced below. One identifies Leeds in the foreground (Fritz Mathiesen in the background) at a damaged railroad bridge between Anchorage and Seward several weeks after the March 27th event. The second photograph below is perhaps the most photographed steel column damage ever, showing the buckled and torn, large steel column of the Cordova building in Anchorage.
National Earthquake Resilience : Research, Implementation, and Outreach (National Academy of Sciences, Board on Earth Sciences and Resources, 2011) interprets earthquake resilience broadly to incorporate engineering/science (physical), social/economic (behavioral), and institutional (governing) dimensions. The example of a massive earthquake in northern Japan causing a tsunami, cutting electrical power supplies, and stopping the pumps needed to cool nuclear reactors, resulting in a nuclear radiation crisis demonstrates the cascading nature of earthquake risk and the potential complex threat that earthquakes pose to modern societies. Such compound disasters can strike any earthquake-prone populated area. National Earthquake Resilience presents a consensus, uncritical roadmap for increasing national resilience to earthquakes. Resilience encompasses both pre-disaster preparedness activities and post-disaster response. In combination, these will enhance the robustness of communities in all earthquake-vulnerable regions of the nation so that communities can function ‘adequately’ following damaging earthquakes. National Earthquake Resilience is written primarily for the NEHRP audience, it also speaks to a broader audience of policy makers, earth scientists, and emergency managers.
(extracted and edited from NAS publication announcement – cdj)
The 2010 Haiti earthquake catastrophe might suggest that because hurricanes represent an annual hazard to most Caribbean nations, the return period for severe earthquakes in the Caribbean region is too long to assure some degree of sovereign preparedness, risk mitigation and risk transfer. So it may be prudent to recall that on June 7, 1692, Port Royal, colonial Jamaica (population of 6,500, across the harbor from the present-day Kingston) was destroyed by several minutes of severe ground shaking, liquefaction of the sands beneath the town, and a large tsunami produced by a strong earthquake (estimated at M=7.5 today).
Caribbean seismic history and patterns of regional seismicity are well detailed in contemporary publications. (See: Sykes, L. R.; Ewing, W. M., (1965) “The seismicity of the Caribbean Region…” ; Tomblin, Judith M. and Robson, Geoffrey R., (1977) “A catalogue of felt earthquakes for Jamaica…” ; Pereira, John A. , (1979) “The Frequency of damaging earthquakes in Jamaica …” ; Bakun, William H. et al. , (2012) “Significant Earthquakes on the Enriquillo Fault System, Hispaniola, 1500–2010: Implications for Seismic Hazard…” ; Mann P. et al., (2007) “Toward a better understanding of the Late Neogene strike-slip restraining bend in Jamaica: geodetic, geological, and seismic constraints” …). Today seismic hazards in Jamaica and surrounding areas are monitored instrumentally (See: University of the West Indies, -Jamaica earthquakes). Seismic basis for engineering design decisions are established (For example: Tomblin, John F., (1978) “Earthquake parameters for engineering design in the Caribbean…). Seismic constraints, risk potential, including expected losses from natural disasters of hurricanes, wind, flooding, earthquake, and tsunami can be realistically assessed (For example – Reinsurance Offices Association , (1976) “Jamaica earthquakes…” ; Lynch, Lloyd and Salazar, Walter, “Earthquake risk reduction …”) within state natural hazard response planning, within Caribbean regional preparedness (See: Seismic Research Center, University of West Indies, Trinidad and Tobago), and within international work like the Global Earthquake Model. (See: SwissRe and GEM).
|Shake table, seismic testing and performance evaluation of several innovative highway bridge columns designed to eliminate post-earthquake residual displacements and minimize column damage in strong earthquakes were presented to the “Bridge Resilience for Earthquakes and Other Natural Hazards” themed Seventh National Seismic Conference on Bridges & Highways (Oakland, California, May 20-22, 2013). Highway bridge column designs used pre-cast, Hybrid Fiber Reinforced Concrete (HyFRC) and post-tensioned steel strands (methods are elaborated in a 2011 PEER Report), or HyFRC with unbonded pre-tensioned steel strands, or prefabricated dual-steel shells. Carbon fiber reinforced polymer (CFRP) wrap was used to repair and strengthen the columns before subsequent testing. All tri-axial shake table tests of one-third scale specimens are reported with reference to a conventional reinforced concrete bridge column test specimen.|
Three experimental methods dominate laboratory research on the seismic performance of structural systems — shake table tests, quasi-static tests, and hybrid simulation. (See: M.S. Williams and A. Blakeborough, “Laboratory testing of structures under dynamic loads: an introductory review” in Theme Issue ‘Dynamic testing of structures’ compiled by M.S. Williams; Philosophical Transactions A of the Royal Society. September 15, 2001; 359 (1786). Costs of shake table tests (especially to avoid scaling problems) and the dynamic limits of most static testing procedures have propelled cost-effective hybrid simulation test methods. Hybrid simulation techniques combine physical, experimental testing of subassemblages (substructured components that can be full-scale) under simulated earthquake loadings with simultaneous numerical simulations of multiple other substructures into one model. Subassemblages tested experimentally are usually portions of the structure that are very difficult to model numerically, while components with predictable behavior are modeled on the computer.
The first operational hybrid simulated testing in earthquake engineering occurred 40 years ago at the University of Tokyo. (See – Takanashi, Koichi. Non-linear earthquake response analysis of structures by a computer-actuator on-line system (detail of the system); article first published in English in: Bulletin of Earthquake Resistant Structure Research Center (The Institute of Industrial Science, University of Tokyo), No.8, December, 1974. p.1-17., 1975; and subsequently, Takanashi, Koichi and Nakashima, M. “Japanese activities on on-line testing” Journal of Engineering Mechanics, ASCE, 113 (7) : July, 1987 p. 1014-1032.)
The hybrid simulation testing techniques of analytical simulation and substructure testing methods are rooted in the development of ‘pseudo-dynamic testing’ methods (See: Shing, Pui-shum B.; Mahin, Stephen A. Experimental error propagation in pseudodynamic testing. UCB/EERC-83/12, Earthquake Engineering Research Center, University of California, Berkeley, 1983-06, 175 pages. ; Shing, Pui-shum B.; Mahin, Stephen A. Pseudodynamic test method for seismic performance evaluation: theory and implementation. UCB/EERC-84/01, Earthquake Engineering Research Center, University of California, Berkeley, 1984-01, 162 pages ; Dermitzakis, Stavros N.; Mahin, Stephen A. Development of substructuring techniques for on-line computer controlled seismic performance testing. UCB/EERC-85/04, Earthquake Engineering Research Center, University of California, Berkeley, 1985-02, 153 pages ; Thewalt, Christopher R.; Mahin, Stephen A. Hybrid solution techniques for generalized pseudodynamic testing. UCB/EERC-87/09, Earthquake Engineering Research Center, University of California, Berkeley.) This continuous development of substructuring techniques, significant improvements in control technology, and repeated experimental implementation resulted in successful geographically-distributed hybrid simulation tests by early 2000s, (See – Mosqueda, Gilberto; Stojadinovic, Bozidar; Mahin, Stephen A. Continuous hybrid simulation with geographically distributed substructures. UCB/EERC-2005/02, Earthquake Engineering Research Center, University of California, Berkeley, 2005-11, 168 pages) as well as the emergence at UC Berkeley of the Open System for Earthquake Engineering Simulation – OpenSees - and the Open-source Framework for Experimental Setup and Control – OpenFresco - , open source software that support hybrid simulation for seismic performance testing.
Seismic performance testing using hybrid simulation techniques is now in wide use. Some widely drawn examples include : [US-Japan] Peng Pan, Hiroshi Tomofuji, Tao Wang, Masayoshi Nakashima, Makoto Ohsaki, Khalid M. Mosalam. “Development of peer-to-peer (P2P) internet online hybrid test system.” Earthquake Engineering & Structural Dynamics, Volume 35, Issue 7, pages 867–890, June 2006. [China] Jiang Wang, Jin-Ting Wang , Feng Jin, Fu-Dong Chi, Chu-Han Zhang. “Real-time dynamic hybrid testing for soil–structure interaction analysis.” Soil Dynamics and Earthquake Engineering. Volume 31, Issue 12, December 2011, Pages 1690–1702. [Europe] F. J. Molina, G. Magonette and B. Viaccoz . Linear Model of a Pseudo-Dynamic Testing System. European Commission, Joint Research Centre (JRC) Scientific and Technical Reports , IPSC, ELSA Laboratory, Ispra (VA), Italy. 2002; Santacana, Ferran Obón; Dorka, Uwe E. “Effects of large numerical models in continuous hybrid simulation.” Lisboa, Portugal. WCEE, 2012, paper presented at 15th World Conference on Earthquake Engineering; Tsitos, A. C.; Bousias, S.; Dimitropoulou, E. “Hybrid testing of bridge structures supported on elastomeric bearings.” Lisboa, Portugal. WCEE, 2012, paper presented at 15th World Conference on Earthquake Engineering; [USA] Nakata, Narutoshi; Elnashai, A. S.; Spencer, Billie F. “Multi-dimensional mixed-mode hybrid simulation control and applications.” University of Illinois at Urbana-Champaign, Newmark Structural Engineering Laboratory Report Series 005, 2007-12; [Canada] Kammula, V.; Erochko, J.; Kwon, O.; Christopoulos, Constantin. “Performance assessment of the self centering energy dissipative (SCED) bracing system using hybrid simulation.” Lisboa, Portugal. WCEE, 2012, paper presented at 15th World Conference on Earthquake Engineering.
Any semi-organized deployment of engineers, geologists, seismologists, sociologists, economists, and the other professionals attracted to immediate, post-damaging earthquake locales in California requires some planning and clear agency responsibilities to avoid chaos.
|A California Post-Earthquake Information Clearinghouse, established after the San Fernando earthquake in 1972 to coordinate observations and knowledge-sharing among emergency responders and the engineering and scientific communities, provides an organizational planning focus (See: 2013 ‘Golden Guardian’ exercise) for post-earthquake study and response. Although California law since at least 1971 requires municipalities to have seismic safety plans, coordination issues among cities and other levels of government in their quest for resources and assistance in post-earthquake scenarios are well-documented (See for example: Nigg, J.M. (1998) “Emergency response following the 1994 Northridge earthquake: intergovernmental coordination issues”). Training and coordination of non-emergency, post earthquake actions are continuously re-evaluated as engineering knowledge changes (See for example : Bazzurro, P. (2004) “Guidelines for seismic assessment of damaged buildings” or, Harthorn, R.W. (1998) “Temporary shoring & stabilization of earthquake damaged historic buildings : practical considerations for earthquake response & recovery in California” or the ongoing CalEMA – ATC20 training classes for post-earthquake inspections) and as new clearinghouse information-tools emerge for field use.|
The California Earthquake Clearinghouse provides a management platform for coordinated planning, discussion and review of local, state and federal agency responsibilities between earthquakes — and coordinated action immediately after larger earthquakes in California.
Extra credit: Musical relief for the California-earthquake-weary from the late, Warren Zevon or consideration of the potential flooding hazards in a predicted ARkStom for the state of California.