Map Sheet 48 (2025 update) - Ground Motion from SA20 (10% in 50 years)

This image service is part of a collection of maps for PGA, PGV and spectral accelerations at 0.2 s (SA02), 1.0 s (SA10), and 2.0 s (SA20) to illustrate seismic hazards in California. For each ground motion parameter, maps at two different hazard levels were presented: one with a 2% probability of being exceeded in 50 years (equivalent to 2,475-year recurrence interval) and the other with 10% probability of being exceeded in 50 years (equivalent to 475-year recurrence interval). The ArcGIS Online interface allows users to select any two ground motion hazard maps to compare side by side. Ground motion parameters were calculated using the 2023 update of the U.S. Geological Survey National Seismic Hazard Model. See the “Scientific Background” on MS48 webpage for detailed information. Due to software limitations, symbology cannot be added to this service. To match the symbology used in the MS48 Ground Motion application, use the following configuration: Esri Color Ramp: Magma Minimum: 4.41 g Maximum: 0.032 g Gamma: 1本影像服务为一套用于展示加利福尼亚州地震灾害的地图集的组成部分，涵盖峰值地面加速度（Peak Ground Acceleration, PGA）、峰值地面速度（Peak Ground Velocity, PGV），以及0.2秒谱加速度（Spectral Acceleration at 0.2s, SA02）、1.0秒谱加速度（SA10）与2.0秒谱加速度（SA20）。针对每一类地面运动参数，本数据集提供了两种不同灾害水准下的地图：其一为50年内超越概率2%（对应重现期2475年），其二为50年内超越概率10%（对应重现期475年）。ArcGIS Online（ArcGIS在线）界面支持用户任选两幅地面运动灾害地图进行并排对比。地面运动参数基于美国地质调查局（U.S. Geological Survey, USGS）2023年更新版的国家地震灾害模型计算得到。详细信息请参阅MS48网页的「科学背景」版块。受软件限制，本服务无法添加符号化样式。若需与MS48地面运动应用中使用的符号系统保持一致，请采用以下配置：Esri色彩渐变（Color Ramp）：Magma；最小值：4.41 g；最大值：0.032 g；伽马值：1。