Earthquake Hazard Maps Research Articles

Bayes and BOGSAT: Issues in When and How to Revise Earthquake Hazard Maps

Recent large earthquakes that caused ground shaking larger than anticipated have generated interest in how to improve earthquake hazard mapping. Issues under discussion include how to evaluate maps’ performance, how to assess their uncertainties, how to make better maps, and how to best use maps given their limitations. An important question is what to do after an earthquake yielding shaking larger than anticipated. Hazard mappers have two choices. One is to regard the high shaking as a low‐probability event allowed by the map, which used estimates of the probability of future earthquakes and the resulting shaking to predict the maximum shaking expected with a certain probability over a given time (Hanks et al. , 2012; Frankel, 2013). The usual choice, however, is to accept that high shaking was not simply a low‐probability event consistent with the map, and revise the map to show increased hazard in the heavily shaken area (Fig. 1). Figure 1. (top) Japanese seismic‐hazard maps before and after the 2011 Tohoku earthquake. The predicted hazard has been increased both along the east coast, where the 2011 earthquake occurred, and on the west coast. (http://www.j-shis.bosai.go.jp/map/?lang=en; last accessed December 2014.) (bottom) Comparison of successive Italian hazard maps (Stein et al. , 2013). The 1999 map was updated to reflect the 2002 Molise earthquake, and the 2006 map will likely be updated after the 2012 Emilia earthquake. Whether and how much to revise a map is complicated, because a new map that better describes the past may or may not better predict the future. For example, increasing the predicted hazard after an earthquake on a fault will make better predictions if the average recurrence time is short compared to the map’s time window but will overpredict future shaking if the average recurrence time is much longer than the map’s time window. …

Global earthquake and volcanic eruption risk management activities, volcanic hazard assessment support system and Asia-Pacific region hazard mapping project in G-EVER

The Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management (G-EVER) Consortium among the Asia-Pacific geohazard research institutes was established in 2012 with the main objective of reducing the risk caused by earthquakes, tsunamis and volcanic eruptions world-wide. The first G-EVER workshop was held in Tsukuba, Japan in February 2012. The G-EVER1 accord was approved by the workshop participants which made 10 recommendations that focused on the enhancement of collaboration, sharing of resources and making information about the risks of earthquakes and volcanic eruptions freely available and understandable. The G-EVER Promotion Team in Geological Survey of Japan was organized in Nov. 2012 to coordinate the G-EVER related activities. The G-EVER Hub website was setup to promote the exchange of information and knowledge about volcanic and seismic hazards among the Asia-Pacific countries. Establishing or endorsing data interchange and analytical methods standards for geohazard institutes of the world are important to promote data sharing and comparative analyses. Several G-EVER Working Groups and projects were proposed such as the Next-generation volcanic hazard assessment WG and the Asia-Pacific region earthquake and volcanic hazard mapping project. The volcanic assessment support system is developed based on eruption history, volcanic eruption database and numerical simulations. The G-EVER hazard assessment support system is implemented with user-friendly interface, making the risk assessment system easy to use and accessible online. The Asia-Pacific region earthquake and volcanic hazard mapping project aims to make a sophisticated online hazard information system that provides past and recent earthquake and volcanic hazards information, risk assessment tools for earthquake and volcanic eruption hazards and links to global earthquake and volcanic eruption databases. The hazard mapping project plans to create the system with the cooperation of Asia-Pacific countries.

Application of geographical information system for mapping/monitoring seismological hazards in Pakistan

This study attempts to use the geographic information system (GIS) technique to map and understand the tectonics and crustal structures of Pakistan. Maps of surficial tectonic features and seismological parameters including Moho depth, Pn velocity and Pg velocity are complied. Based on the seismological data-set of the country the earthquake hazard map of Pakistan is also presented by applying regression technique on seismological, geological and topographical parameters. A case study of 8 October 2005 earthquake is used to validate the hazard map. It is envisaged that the developed GIS database would help policy-makers and scientists in natural hazard evaluation, seismic risk assessment and understanding of earthquake occurrences in Pakistan.

Communicating the Value of Science

The quality of life Americans enjoy today and the United States's ability to compete in the global economy have many of their roots in the country's long history of leadership in scientific research and discovery. Federally supported basic research has led to innovations such as GPS, earthquake hazard mapping, and hundreds of technological spinoffs from the space program, including heart monitors and material that protects us from fire.

Net earthquake hazard and elements at risk (NEaR) map creation for city of Istanbul via spatial multi-criteria decision analysis

The creation of earthquake hazard maps requires various datasets with selected attenuation relations. Based on the selected attenuation relation, the calculation time varies from half an hour to a couple of days. The length of time needed to create an earthquake hazard map also depends on the resolution of the resulting map. The time gets longer as the resolution of the resulting earthquake hazard map gets higher. The basic form of an attenuation relation requires complex calculation algorithms including geospatial information related to the region of interest. Nowadays, next-generation attenuation (NGA) models are introduced to generate more realistic earthquake hazard maps. However, the more complex the attenuation relation is, the longer time will be required to create a hazard map. This paper offers a new method to create high-resolution earthquake hazard maps, faster than using traditional attenuation relation methods, by using an analytic hierarchy process of spatial multi-criteria decision analysis and geographic information systems. This method has been generated and tested for the city of Istanbul. The resulting maps are compared with the earthquake hazard maps created for the city of Istanbul by using the NGA model of Boore and Atkinson (in Boore–Atkinson NGA ground motion relations for the geometric mean horizontal component of peak and spectral ground motion parameters (trans: Engineering Co, University of California B). Pacific Earthquake Engineering Research Center 2007). A second output of this paper is a map of the elements at risk (EaR) for the population and buildings of Istanbul, and the introduction of a new approach of net elements at risk (NEaR).

The 2013 Lushan Earthquake in China Tests Hazard Assessments

Online Material: Earthquake hazard map; figures showing geodynamic and elastic block models; and table of M s>6 earthquakes used in the study. Following the devastating 2008 Wenchuan earthquake that ruptured the central–northern segments of the Longmenshan fault in Sichuan, China, many studies assessed its impact on other major faults in this region (e.g., Parsons et al. , 2008; Toda et al. , 2008). On 20 April 2013, the M w 6.6 Lushan earthquake ruptured the southern segment of the Longmenshan fault, allowing these assessments to be tested. The 2008 Wenchuan earthquake ( M w 7.9) came as a surprise, because the Longmenshan fault zone, which separates the growing Tibetan Plateau from the rigid Sichuan basin (Fig. 1), slips slowly (less than 3 mm/yr; Shen et al. , 2009); with only moderate seismicity (Burchfiel et al. , 2008; Wang et al. , 2010). The earthquake‐hazard map by the Global Seismic Hazard Assessment Program shows the entire Longmenshan fault zone as being relatively safe, as shown in ![Graphic][1] Figure S1 (available in the electronic supplement to this paper). Figure 1. Topography (color contours), faults (lines), and seismicity (dots) of eastern Tibetan Plateau and Sichuan basin. Gray dots, historic events; red dots, instrumentally recorded events; beach ball, fault plane solution and aftershock sequence of the 2008 Wenchuan earthquake are in light blue; those for the 2013 Lushan earthquake are in dark blue. Epicenters are from the China Earthquake Data Center (http://data.earthquake.cn/data, last accessed April 2013). Inset map shows the location of the map region. The same cannot be said for the M w 6.6 Lushan earthquake, which occurred in the morning of … [1]: /embed/inline-graphic-1.gif

Corrigendum to comment on “Why Earthquake Hazard Maps Often Fail and What to do About It” by S. Stein, R. Geller, and M. Liu [TECTO 592(2013) 200–206

Corrigendum to comment on “Why Earthquake Hazard Maps Often Fail and What to do About It” by S. Stein, R. Geller, and M. Liu [TECTO 592(2013) 200–206

Making sense of Australian earthquakes: the Ambraseys legacy

Through his students, Professor Nick Ambraseys has had a strong impact on the introduction of earthquake engineering practices in Australia, including historical earthquake studies, strong motion instrumentation and analysis, foundation studies including liquefaction, and building code formulation. In Australia the process of upgrading the third and current edition of the earthquake code and hazard map has begun. There are now about 150 digital strong motion recorders installed in cities, on major structures and at Australian National Seismograph Network sites. Three volumes of an isoseismal atlas have been published totalling more than 300 maps, mainly historical earthquakes. Significant progress has been made in paleoseismological studies across the continent, adding to the complexity of the intraplate seismicity model. With time and more installed accelerographs, the peak ground acceleration recorded in Australia has increased from .25 g in 1984 to .5 g in 1988 and 1 g in 1994, all from earthquakes smaller than magnitude 5, supporting Ambraseys contention that PGA alone is not a suitable parameter for a design ground motion.

The earthquake and tsunami hazard map of 1854

The earthquake and tsunami hazard map of 1854

Spatial mapping of earthquake hazard parameters in the Hindukush–Pamir Himalaya and adjacent regions: Implication for future seismic hazard

The study deals spatial mapping of earthquake hazard parameters like annual and 100-years mode along with their 90% probability of not being exceeded (NBE) in the Hindukush–Pamir Himalaya and adjoining regions. For this purpose, we applied a straightforward and most robust method known as Gumbel’s third asymptotic distribution of extreme values (GIII). A homogeneous and complete earthquake catalogue during the period 1900–2010 with magnitude MW⩾4.0 is utilized to estimate these earthquake hazard parameters. An equal grid point mesh, of 1° longitude X 1° latitude, is chosen to produce detailed earthquake hazard maps. This performance allows analysis of the localized seismicity parameters and representation of their regional variations as contour maps. The estimated result of annual mode with 90% probability of NBE is expected to exceed the values of MW 6.0 in the Sulaiman–Kirthar ranges of Pakistan and northwestern part of the Nepal and surroundings in the examined region. The 100-years mode with 90% probability of NBE is expected to exceed the value of MW 8.0 in the Hindukush–Pamir Himalaya with Caucasus mountain belt, the Sulaiman–Kirthar ranges of Pakistan, northwestern part of the Nepal and surroundings, the Kangra–Himanchal Pradesh and Kashmir of India. The estimated high values of earthquake hazard parameters are mostly correlated with the main tectonic regimes of the examined region. The spatial variations of earthquake hazard parameters reveal that the examined region exhibits more complexity and has high crustal heterogeneity. The spatial maps provide a brief atlas of the earthquake hazard in the region.

Reply to comment by Arthur Frankel on “Why Earthquake Hazard Maps Often Fail and What to do About It”

Earthquake hazard maps are produced to tell the public that some areas are more at risk than others, and to help governments prepare appropriately. To the extent a hazard map proves accurate, it helps society protect itself against earthquake damage. On the other hand, an inaccurate hazard map may lead to either inadequate preparation or suboptimal use of limited resources (Stein and Stein, in press). As we noted in our original paper, Stein et al. (2012), cited as SGL2012 below, the March 11, 2011 Tohoku, Japan, earthquake is a classic and unfortunate example of what can go wrong. Japan's national hazard map said (and still says) that the Tokai region (along the Pacific coast from Shizuoka to Nagoya) and the Tonankai and Nankai regions (farther to the west) had the highest hazard, with the hazard in Tohoku being considerably smaller. This indirectly led to a relatively low level of countermeasures in Tohoku generally and at the Fukushima Dai-ichi nuclear power plant in particular, which contributed to an unnecessarily large number of casualties and property damage, including the level-7 nuclear accident at Fukushima (Geller, 2011; Noggerath et al., 2011). The 2011 Tohoku earthquake is, alas, not an isolated example. As pointed out by SGL2012, the 2003 Algeria earthquake, 2004 Morocco earthquake, 2008 Wenchuan earthquake, and 2010 Haiti earthquake all also occurred in regions mapped as relatively low hazard. SGL2012 also cited work (Reyners, 2011) that showed that the February 22, 2011 Mw6.3 earthquake, which did considerable damage in Christchurch, New Zealand, produced much stronger ground motion than the hazard map predicted would occur in the

Comment on “Why earthquake hazard maps often fail and what to do about it” by S. Stein, R. Geller, and M. Liu

Stein et al. (2012) contends that the occurrence of some recent destructive earthquakes in areas mapped as low hazard in some probabilistic seismic hazard maps “illustrates limitations of earthquake hazard mapping.” This statement is fundamentally incorrect. These instances illustrate that short-term observations such as recent seismicity do not characterize the hazard from faults with long recurrence-time earthquakes. This is not an inherent limitation in the methodology of probabilistic seismic hazard assessment (PSHA). They repeat arguments made in their previous articles, one of them recent (Stein et al., 2011) and others on the New Madrid region of the central United States that were published and commented on several years ago (e.g., Frankel, 2003, 2004; Stein et al., 2003). Stein et al. (2012) makes three major points: 1) the inputs to seismic hazard maps should include long-term geologic data in addition to historical and instrumental seismicity, 2) uncertainties in hazard values should be estimated and communicated to users, and 3) seismic hazard maps need to be objectively tested. The first two points have long been recognized and practiced in the seismic hazard mapping community in the United States and elsewhere. The third point has also been the subject of substantial work (e.g., Stirling and Petersen, 2006). This comment points out problems

Comment on "Earthquake Hazard Maps and Objective Testing: The Hazard Mapper's Point of View" by Mark W. Stirling

Article Commentary| September 01, 2012 Comment on “Earthquake Hazard Maps and Objective Testing: The Hazard Mapper's Point of View” by Mark W. Stirling Jens‐Uwe Klügel Jens‐Uwe Klügel Oberer Rainweg 13, 5070 Frick, Switzerland Search for other works by this author on: GSW Google Scholar Author and Article Information Jens‐Uwe Klügel Oberer Rainweg 13, 5070 Frick, Switzerland Publisher: Seismological Society of America First Online: 14 Jul 2017 Online ISSN: 1938-2057 Print ISSN: 0895-0695 © 2012 by the Seismological Society of America Seismological Research Letters (2012) 83 (5): 829–830. https://doi.org/10.1785/0220120051 Article history First Online: 14 Jul 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jens‐Uwe Klügel; Comment on “Earthquake Hazard Maps and Objective Testing: The Hazard Mapper's Point of View” by Mark W. Stirling. Seismological Research Letters 2012;; 83 (5): 829–830. doi: https://doi.org/10.1785/0220120051 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search In his opinion paper “Earthquake Hazard Maps and Objective Testing: The Hazard Mapper’s Point of View,” Stirling (2012) makes the claim that probabilistic seismic hazard (PSH) maps “are tools developed to provide estimates of hazard for long return periods (e.g., hundreds to thousands of years)” (p. 231). He is referring to the applications of PSH models for nuclear facilities and hydro dam developments as successful examples of the probabilistic method. Stirling is recommending PSH applications such as the Yucca Mountain seismic project also for other areas. Despite Stirling’s opinion, PSH maps in use today obviously should not be used for... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Earthquake Hazard Maps and Objective Testing: The Hazard Mapper's Point of View

Editorial| March 01, 2012 Earthquake Hazard Maps and Objective Testing: The Hazard Mapper’s Point of View Mark W. Stirling Mark W. Stirling GNS Science P.O. Box 30368 Lower Hutt, New Zealandm.stirling@gns.cri.nz Search for other works by this author on: GSW Google Scholar Seismological Research Letters (2012) 83 (2): 231–232. https://doi.org/10.1785/gssrl.83.2.231 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Mark W. Stirling; Earthquake Hazard Maps and Objective Testing: The Hazard Mapper’s Point of View. Seismological Research Letters 2012;; 83 (2): 231–232. doi: https://doi.org/10.1785/gssrl.83.2.231 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search The recent SRL Opinion article titled “Bad Assumptions or Bad Luck: Why Earthquake Hazard Maps Need Objective Testing,” by Seth Stein, Robert Geller, and Mian Liu (SRL 82(5), 623–626) suggests that probabilistic seismic hazard (PSH) models have been inadequate in terms of forecasting recent devastating earthquakes, and expresses a need for objective testing of these models. This response comes from the perspective of a hazard mapper. First, I’d like to clarify that the PSH models referred to by Stein and his colleagues are not forecasting tools. They are tools developed to provide estimates of hazard for long return periods... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Analysis of earthquake parameters to generate hazard maps by integrating AHP and GIS for Küçükçekmece region

Abstract. Definition of an earthquake includes parameters with respect to region of interest. Each of those parameters has different weights on the earthquake ground motion and effect. This study examines the weight of common parameters that have an influence on the effects of earthquakes. The Analytic Hierarchy Process (AHP) is used for factor weighting of each parameter and Geographic Information Systems (GIS) are used for simulating the results of the AHP on a spatial environment. In this study, it is aimed to generate a hierarchical structure of the model for the simulation of an earthquake hazard map (EHM). The parameters of the EHM, which are selected by the criterion of non-correlated factors, are: topography, distance to epicenter, soil classification, liquefaction, and fault/focal mechanism. As a result of the study, weights of the parameters that affect the earthquake ground motion at the study area are determined and compared with a selected attenuation relation map.

A GIS-based software for lifeline reliability analysis under seismic hazard

Lifelines are vital networks, and it is important that those networks are still functional after major natural disasters such as earthquakes. Assessing reliability of lifelines requires spatial analysis of lifelines with respect to a given earthquake hazard map. In this paper, a GIS-based software for the spatial assessment of lifeline reliability which is developed by using GeoTools environment is presented. The developed GIS-based software imports seismic hazard and lifeline network layers and then creates a gridded network structure. Finally, it adopts a network reliability algorithm to calculate the upper and lower bounds for system reliability of the lifeline under seismic hazard. The software enables user visualizing the reliability values in graphical form as well as thematic lifeline reliability map with colors indicating reliability level along with the link and the overall network. It also provides functions for saving the analysis results in shape file format. The software is tested and validated for an application taken from literature which is a part of water distribution system of Bursa in Turkey. The developed GIS-based software module that creates GIS-based reliability map of the lifelines under seismic hazard is user friendly, modifiable, fast in execution time, illustrative and validated for the existing literature studies.

Bad Assumptions or Bad Luck: Why Earthquake Hazard Maps Need Objective Testing

During World War II, future Nobel Prize winner Kenneth Arrow served as a military weather forecaster. “My colleagues had the responsibility of preparing long-range weather forecasts, i.e. , for the following month,” he wrote. “The statisticians among us subjected these forecasts to verification and found they differed in no way from chance. The forecasters themselves were convinced and requested that the forecasts be discontinued. The reply read approximately like this: `The commanding general is well aware that the forecasts are no good. However, he needs them for planning purposes.'” (Gardner 2010). Seismologists often encounter a similar situation when developing earthquake hazard maps, which ideally describe the level of earthquake hazards in a region and provide a scientific foundation for earthquake preparation and mitigation. However, in recent years many large and destructive earthquakes have occurred in places mapped as having relatively low hazard (Kerr 2011). A striking example is the March 2011 M 9.1 earthquake off Tohoku, Japan, which occurred in an area shown by the Japanese national earthquake hazard map as one of relatively low hazard. Figure 1, from Geller (2011), illustrates his point that ...in recent years many large and destructive earthquakes have occurred in places mapped as having relatively low hazard... The regions assessed as most dangerous are the zones of three hypothetical “scenario earthquakes” (Tokai, Tonankai, and Nankai; see map). However, since 1979, earthquakes that caused 10 or more fatalities in Japan actually occurred in places assigned a relatively low probability. This discrepancy—the latest in a string of negative results for the characteristic earthquake model and its cousin, the seismic-gap model—strongly suggests that the hazard map and the methods used to produce it are flawed and should be discarded. Similar discrepancies have occurred around the world. The 2008 Wenchuan earthquake (M 7.9) in China occurred …

Cultural Heritage Sites in Shiga Prefecture in Danger of Natural Disasters

Natural disasters threaten all human efforts, from everyday living to cultural heritage site preservation. To protect them, such sites must first be identified. We conducted two studies on cultural monuments designated by the law as The National Treasures and Important Cultural Properties in Shiga prefecture to evaluate potential of damage from natural disasters – first, focusing on cultural monument damage via a bibliographic survey and, second, looking at potential of damage via geographic information systems (GIS) combining earthquake and flood hazard maps, sediment disaster warning maps, and an architectural monuments map. We also analyzed the geological aspects of historical sediment disasters. From our findings, we conclude the following: • Most structural damage was due to typhoons. • The eight sites most potentially subject to earthquake damage are concentrated on the west coast of Lake Biwa. • By type, 8 sites are threatened by earth flows, 5 by debris flows, and 2 by landslides. • Many sites historically subject to debris flows and earth flows are within 1 kilometer of a geological discontinuity or an active fault.

Simplified Method for Spatial Evaluation of Liquefaction Potential in the St. Louis Area

As a part of an earthquake hazard mapping program being undertaken by the U.S. Geological Survey in the St. Louis metropolitan area, surficial geologic mapping and subsurface geotechnical data have been compiled into a three-dimensional geographic information system (GIS). The potential for soil liquefaction was then spatially evaluated by using subsurface information from 562 boreholes for an assumed M7.5 earthquake emanating from the New Madrid Seismic Zone. Geotechnical data (standard penetration test N-values, overburden pressure, and depth-to-groundwater) and the scenario peak ground accelerations (PGA=0.1, 0.20, and 0.30 g) were applied to evaluate the factor of safety (FS) against earthquake-induced liquefaction. The liquefaction potential index (LPI) method was used in these evaluations because it allows for calculations of FS with depth for 10–25 discrete stratigraphic horizons overlying the bedrock across the St. Louis metropolitan area. LPI values were derived from the correlation between calc...

History of Modern Earthquake Hazard Mapping and Assessment in California Using a Deterministic or Scenario Approach

Modern earthquake ground motion hazard mapping in California began following the 1971 San Fernando earthquake in the Los Angeles metropolitan area of southern California. Earthquake hazard assessment followed a traditional approach, later called Deterministic Seismic Hazard Analysis (DSHA) in order to distinguish it from the newer Probabilistic Seismic Hazard Analysis (PSHA). In DSHA, seismic hazard in the event of the Maximum Credible Earthquake (MCE) magnitude from each of the known seismogenic faults within and near the state are assessed. The likely occurrence of the MCE has been assumed qualitatively by using late Quaternary and younger faults that are presumed to be seismogenic, but not when or within what time intervals MCE may occur. MCE is the largest or upper-bound potential earthquake in moment magnitude, and it supersedes and automatically considers all other possible earthquakes on that fault. That moment magnitude is used for estimating ground motions by applying it to empirical attenuation relationships, and for calculating ground motions as in neo-DSHA (Zuccoloet al., 2008). The first deterministic California earthquake hazard map was published in 1974 by the California Division of Mines and Geology (CDMG) which has been called the California Geological Survey (CGS) since 2002, using the best available fault information and ground motion attenuation relationships at that time. The California Department of Transportation (Caltrans) later assumed responsibility for printing the refined and updated peak acceleration contour maps which were heavily utilized by geologists, seismologists, and engineers for many years. Some engineers involved in the siting process of large important projects, for example, dams and nuclear power plants, continued to challenge the map(s). The second edition map was completed in 1985 incorporating more faults, improving MCE’s estimation method, and using new ground motion attenuation relationships from the latest published results at that time. CDMG eventually published the second edition map in 1992 following the Governor’s Board of Inquiry on the 1989 Loma Prieta earthquake and at the demand of Caltrans. The third edition map was published by Caltrans in 1996 utilizing GIS technology to manage data that includes a simplified three-dimension geometry of faults and to facilitate efficient corrections and revisions of data and the map. The spatial relationship of fault hazards with highways, bridges or any other attribute can be efficiently managed and analyzed now in GIS at Caltrans. There has been great confidence in using DSHA in bridge engineering and other applications in California, and it can be confidently applied in any other earthquake-prone region. Earthquake hazards defined by DSHA are: (1) transparent and stable with robust MCE moment magnitudes; (2) flexible in their application to design considerations; (3) can easily incorporate advances in ground motion simulations; and (4) economical. DSHA and neo-DSHA have the same approach and applicability. The accuracy of DSHA has proven to be quite reasonable for practical applications within engineering design and always done with professional judgment. In the final analysis, DSHA is a reality-check for public safety and PSHA results. Although PSHA has been acclaimed as a better approach for seismic hazard assessment, it is DSHA, not PSHA, that has actually been used in seismic hazard assessment for building and bridge engineering, particularly in California.