A Next GenerationVS30Map for California Based on Geology and Topography

Wills, Christopher; Gutiérrez, Celedonio; Perez, Florante G.; Branum, David M.

doi:10.1785/0120150105

Cited by 106 publications

(58 citation statements)

References 20 publications

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“…Plateau (23%) (×2.1), erosional plain (16%), dunefield (14%), sand plain (10%), low hills (9%), rises (8%), hills (6%), depositional plain (6%) Wills et al (2015) Australia, geological unit reclassified c from Blake and Kilgour (1998) Australia, major landform unit of Chan et al (1986) 10 Holocene alluvium (moderate slopes) (42%) (×6.3), Holocene alluvium (very low slopes) (23%), Pleistocene alluvium (21%) (×2.0), others (14%) Cenozoic regolith (38%), sedimentary rocks (38%), granites (10%), metamorphics (6%), others (8%)…”

Section: Comparison With the Vs30 Data In Japanmentioning

confidence: 99%

“…In addition, a nationwide 7.5 arc-second geomorphological map (Japan Engineering Geomorphologic Classification Map; JEGM, Wakamatsu and Matsuoka 2013) is used nationally for seismic hazard assessments. In California, Wills et al (2000Wills et al ( , 2015 proposed a Vs30 map with the same uses. The map was created by reclassification of the Geologic map of California (Jennings 1977) with the addition of soft-ground regions.…”

Section: Introductionmentioning

confidence: 99%

“…The regolith terrain map used in this study is at a scale of 1:5,000,000 and valley plains were not represented in sufficient detail. For California, we used the Vs30 map of Wills et al (2015), which aggregated and supplemented the geological map of California with estimated seismic amplification. In a general division between hard rocks and unconsolidated strata, Tables 3 and 5 show that Japan and California are alike in that mountains are formed by bedrocks and plains are formed by sediments.…”

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confidence: 99%

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Global terrain classification using 280 m DEMs: segmentation, clustering, and reclassification

Iwahashi

Kamiya²,

Matsuoka

et al. 2018

Prog Earth Planet Sci

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Polygon-based terrain classification data were created globally using 280 m digital elevation models (DEMs) interpolated from the multi-error-removed improved-terrain DEM (MERIT DEM). First, area segmentation was performed globally with the logarithmic value of slope gradient and the local convexity calculated from the DEM. Next, by adding surface texture, k-means clustering was performed globally and the polygons were grouped into 40 clusters. Then, we tried to reclassify these 40 clusters into geomorphologic terrain groups. In this study, we attempted reclassification and grouping using local information from Japan as a test case. The 40 clusters were compared with Japanese geological and geomorphological data and were then reclassified into 12 groups that had different geomorphological and geological characteristics. In addition, large shape landforms, mountains, and hills were subdivided by using the combined texture. Finally, 15 groups were created as terrain groups. Cross tabulations were performed with geological or lithological maps of California and Australia in order to investigate if the Japanese grouping of the clusters was also meaningful for other regions. The classification is improved from previous studies that used 1-km DEMs, especially for the representation of terrace shapes and landform elements smaller than 1 km. The results were generally suitable for distinguishing bedrock mountains, hills, large highland slopes, intermediate landforms (plateaus, terraces, large lowland slopes), and plains. On the other hand, the cross tabulations indicate that in the case of gentler landforms under different geologic provinces/climates, similar topographies may not always indicate similar formative mechanisms and lithology. This may be solved by locally replacing the legend; however, care is necessary for mixed areas where both depositional and erosional gentle plains exist. Moreover, the limit of the description of geometric signatures still appears in failure to detect narrow valley bottom plains, metropolitan areas, and slight rises in gentle plains. Therefore, both global and local perspectives regarding geologic province and climate are necessary for better grouping of the clusters, and additional parameters or higher resolution DEMs are necessary. Successful classification of terrain types of geomorphology may lead to a better understanding of terrain susceptibility to natural hazards and land development.

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Section: Comparison With the Vs30 Data In Japanmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Global terrain classification using 280 m DEMs: segmentation, clustering, and reclassification

Iwahashi

Kamiya²,

Matsuoka

et al. 2018

Prog Earth Planet Sci

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“…In this study, the slope and elevation information of the surface terrain, which may correspond to the major terrain factors related to the geotechnical characteristics, were firstly regarded as topographical indicators and defined as geo-proxies. Studies that evaluate regional seismic response and derive information using proxies from a terrain or geological perspective have been mainly conducted for overseas regions with strong earthquakes [15,17,[28][29][30]. In South Korea, such studies have been conducted at an extremely limited level [31,32] and approaches with verification based on a comprehensive geotechnical DB have not been performed.…”

Section: Framework For Site Classifaction Based On Geo-proxy In Southmentioning

confidence: 99%

Geo-Proxy-Based Site Classification for Regional Zonation of Seismic Site Effects in South Korea

2018

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Seismic site effects and topographic effects related to ground motion occur during an earthquake due to site-specific geotechnical or geological characteristics, including the geological or geographical structure and the characteristics of near-surface sub-soil layers. Site-specific site effects due to geological conditions have been confirmed in recent earthquake events. Earthquake-induced damage has mainly occurred at accumulated soft soil layers under basins or along coasts and rivers. An alternative method has recently been proposed for evaluating regional seismic site effects and amplification factors using digital elevation models (DEM). High-quality DEMs at high resolutions may be employed to resolve finer-scale variations in topographic gradients and consequently, correlated site response parameters. Because there are many regions in South Korea lacking borehole datasets, which are insufficient for site classification only using borehole datasets, a DEM-based proxy for seismic zonation can be effective. Thus, in this study, geo-proxy-based site classification was proposed based on empirical correlations with site response parameters and conducted for regional zonation of seismic site effects to identify the amplification of characteristics in the western metropolitan areas of South Korea, depending on the site-specific geo-spatial conditions.

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“…; Lee and Tsai ; Wills and Clahan ; Wills et al . ; Kanlı et al . ) and are further utilized for generating the ground motion models (e.g.…”

Section: Introductionmentioning

confidence: 99%

V_S₃₀ mapping and site characterization in the seismically active intraplate region of Western India: implications for risk mitigation

Sairam

Singh

Patel

et al. 2019

Near Surface Geophysics

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A B S T R A C TWe carried out shallow subsurface investigations at 600 sites covering all types of geological units in the Northwestern Deccan Volcanic Province of India, using the multichannel analysis of surface waves and suspension PS-logging methods. The results reveal that V S30 values are in the range of 760-1500 m/s for granites and Deccan traps, thus enabling their classification as B-class, as per the National Earthquake Hazard Reduction Program recommendations. The Tertiary, Cretaceous, Jurassic and Paleoproterozoic sediments show V S30 values between 360 and 760 m/s, and hence, are assigned C-class. Further, the Quaternary soils are categorized as D-class, since they show V S30 in the range of 180-360 m/s. Also, the Holocene tidal flat and Rann sediments are classified as E-class, since the V S30 values are less than 180 m/s. The observed site response reveals that the D-and E-type soils have significantly higher seismic amplification than that in the B-and C-category soils. We noticed that the buildings on D-and E-classes soils experienced higher damage than those on the B-and C-classes, during the past large earthquakes in the Northwestern Deccan Volcanic Province. Our study suggests that V S30 is a good proxy for soil classifications in the Northwestern Deccan Volcanic Province. We validated our results using available geological, geophysical and geotechnical data. For the first time, a regional site characterization map for the Northwestern Deccan Volcanic Province of India is prepared based on geology and V S30 .

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A Next GenerationV_S30Map for California Based on Geology and Topography

Cited by 106 publications

References 20 publications

Global terrain classification using 280 m DEMs: segmentation, clustering, and reclassification

Global terrain classification using 280 m DEMs: segmentation, clustering, and reclassification

Geo-Proxy-Based Site Classification for Regional Zonation of Seismic Site Effects in South Korea

V_S₃₀ mapping and site characterization in the seismically active intraplate region of Western India: implications for risk mitigation

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A Next GenerationVS30Map for California Based on Geology and Topography

Cited by 106 publications

References 20 publications

Global terrain classification using 280 m DEMs: segmentation, clustering, and reclassification

Global terrain classification using 280 m DEMs: segmentation, clustering, and reclassification

Geo-Proxy-Based Site Classification for Regional Zonation of Seismic Site Effects in South Korea

VS30 mapping and site characterization in the seismically active intraplate region of Western India: implications for risk mitigation

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A Next GenerationV_S30Map for California Based on Geology and Topography

V_S₃₀ mapping and site characterization in the seismically active intraplate region of Western India: implications for risk mitigation