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

<div style='text-align:justify;'><span style='text-align:start;'>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.</span></div><div style='text-align:justify;'><br /></div><div style='text-align:justify;'><div><font color='#b22222'><i>Due to software limitations, symbology cannot be added to this service. To match the symbology used in the <a href='https://maps.conservation.ca.gov/cgs/ms48/groundmotion/' target='_blank'>MS48 Ground Motion application</a>, use the following configuration:</i></font></div><div><ul><li><font color='#b22222'><i>Esri Color Ramp: Magma</i></font></li><li><i><font color='#b22222'>Minimum: 4.41 g</font></i></li><li><i><font color='#b22222'>Maximum: 0.032 g</font></i></li><li><i><font color='#b22222'>Gamma: 1</font></i></li></ul></div></div>

本影像服务隶属于一套用于展示加利福尼亚州地震危险性的地图集，涵盖峰值地面加速度（PGA）、峰值地面速度（PGV）以及0.2秒谱加速度（SA02）、1.0秒谱加速度（SA10）和2.0秒谱加速度（SA20）等地震动参数的分布图。针对每一类地震动参数，本数据集提供两种不同危险性水准的分布图：其一为50年超越概率2%（对应重现期2475年），其二为50年超越概率10%（对应重现期475年）。ArcGIS Online 界面支持用户任选两张地震动危险性分布图进行并排对比。本次地震动参数基于美国地质调查局（U.S. Geological Survey）2023年更新的全国地震危险性模型计算得到。详细信息请参阅MS48网页上的「科学背景」板块。

由于软件限制，本服务无法添加符号系统。若需匹配<a href='https://maps.conservation.ca.gov/cgs/ms48/groundmotion/' target='_blank'>MS48地震动应用程序</a>中使用的符号系统，请采用以下配置：
- Esri 色彩渐变方案：Magma
- 最小值：4.41 g
- 最大值：0.032 g
- Gamma值：1