Earthquake Spectra Highlights – July 2020

The Earthquake Spectra Editorial Team recommends the following recently released OnlineFIRST articles.


 

PUBLIC POLICY

Incorporating societal expectations into seismic performance objectives in building codes

June 9, 2020 | Alexa Tanner, Stephanie E. Chang, Kenneth J. Elwood

This opinion paper argues that seismic code objectives should reflect how society expects the built environment to perform in an earthquake. Social science methods can be employed to overcome the challenges of understanding what standards society holds for seismic performance… read more

RECOMMENDATION: Tanner, Chang, and Elwood (2020) note that currently, there is little known about what the public actually expects should occur post-earthquake, what risk tolerance levels are, and if the current building codes meet societal expectations. They go on to discuss the importance of incorporating societal expectations in building codes and suggest guiding principles on eliciting public perspectives.



LIFELINES

Fragility curves for toppling of railroad locomotives

June 18, 2020 | Bruce F. Maison

This paper uses three locomotives that overturned (toppled) during strong earthquakes (>6.5M) as computer analytical case studies. The locomotives were at rest or traveling very slowly at the time of the earthquakes. Fragility curves are presented relating ground shaking intensity to the likelihood of toppling… read more

RECOMMENDATION: Bruce Maison’s paper answers the curious question as to what levels of shaking does it take to topple a standard gauge railroad locomotive. Overall, the shaking levels are higher than ground motions often experienced in the western U.S., and there are similar implications for freight and passenger cars with similar characteristics.

 


 

GEOTECHNICAL ENGINEERING 

A global hybrid VS30 map with a topographic slope–based default and regional map insets

June 9, 2020 | David C. Heath, David J. Wald, C. Bruce Worden, Eric M. Thompson, Gregory M. Smoczyk

Time-averaged shear wave velocity over the upper 30 m of the earth’s surface (VS30) is a key parameter for estimating ground motion amplification as both a predictive and a diagnostic tool for earthquake hazards. This paper highlights the development of a new hybrid global VS30 map database that defaults to the global slope-based VS30 map, but smoothly inserts regional VS30 maps where available… read more

RECOMMENDATION: Heath and others present an updated USGS Global Vs30 map and underlying grids. The mosaic map is a hybrid of underlying slope-based Vs30 with smooth insets of regional or national Vs30 maps constrained by other means (Vs30 data, geology, geomorphology, etc.).

 



SOCIAL SCIENCE

Post-earthquake hospital functionality evaluation: The case of Kumamoto Earthquake 2016

June 15, 2020 | Nebil Achour, Masakatsu Miyajima

This paper investigates the impact of damage on the performance of the healthcare service following the 2016 Kumamoto earthquakes. The study connects earthquake metrics and the loss of healthcare service functionality and reveals the reasons for which facilities were totally or partially evacuated… read more

RECOMMENDATION: Following the 2016 Kumamoto earthquakes where the stricken areas lost approximately 15% of their healthcare functionality, Achour and Miyajima found that the current building standards increased the performance of hospital buildings by approximately 10%; though more attention is needed to protect architectural and critical systems.

 


 

PUBLIC POLICY

The role of risk measures in making seismic upgrading decisions

June 11, 2020 | Lukas Bodenmann, Panagiotis Galanis, Marco Broccardo, Božidar Stojadinović

This paper leverages advancements in financial risk management to examine the role of risk measures to quantify the seismically induced financial risk, measure the benefit of seismic upgrading, and relate the benefit of seismic risk reduction to a degree of the implemented seismic upgrade… read more

RECOMMENDATION: Seismic upgrading is an upfront investment without an immediate corresponding gain of the Property’s value. And, communicating benefits of upgrading is difficult without a framework to assess seismic performance in financial terms. Bodenmann et al. show that the selection of the risk measure in quantifying the losses avoided by seismic upgrading of an existing building is crucial in formulating systematic seismic risk mitigation policies.

 


 

STRUCTURAL ENGINEERING

Assessment of the seismic safety of school buildings in Mexico: A first look

June 11, 2020 | Sergio M. Alcocer, José C. Arce, David Murià-Vila, Luciano R. Fernández-Sola, Daniel A Guardia

This paper provides the first comprehensive review of the data and analysis on the seismic performance of school buildings in the aftermath of the 2017 earthquakes… read more

RECOMMENDATION: Alcocer et al. (2020) employ analysis of the observed damage at 12,444 public school buildings across 2,536 campuses in Mexico caused by two earthquakes in September 2017, where about 84% of building stock is made of masonry and concrete. By providing evidence-based information on the observed, measured, and calculated seismic performance (after static analyses) of Mexican school buildings, their study concludes with a series of policy and technical recommendations.