Modified Mercalli Intensity based on the average of horizontal spectral response acceleration for 1.0-second period and peak ground acceleration, with 1-percent probability of exceedance in 1 year

A one-year seismic hazard forecast for the Central and Eastern United States, based on induced and natural earthquakes, has been produced by the U.S. Geological Survey. The model assumes that earthquake rates calculated from several different time windows will remain relatively stationary and can be used to forecast earthquake hazard and damage intensity for the year 2017. This assessment is the first step in developing an operational earthquake forecast for the CEUS, and the analysis could be revised with updated seismicity and model parameters. Consensus input models consider alternative earthquake catalog durations, smoothing parameters, maximum magnitudes, and ground motion estimates, and represent uncertainties in earthquake occurrence and diversity of opinion in the science community. Near some areas of active induced earthquakes, hazard is higher than in the 2014 USGS National Seismic Hazard Model (NSHM) by more than a factor of 3; the 2014 NSHM did not consider induced earthquakes. In some areas, previously observed induced earthquakes have stopped, so the seismic hazard reverts back to the 2014 NSHM. This data set represents the results of calculations of hazard curves for a grid of points with a spacing of 0.05 degrees in latitude and longitude. It represents the average Modified Mercalli Intensity (MMI) with a 1-percent probability of exceedance in 1 year. The MMI values are the average of the MMI values obtained by converting peak ground acceleration to MMI and 1.0-second spectral response acceleration to MMI. The data are for the Central and Eastern United States and are based on the one-year model described above.美国地质调查局（U.S. Geological Survey）基于诱发地震与天然地震数据，完成了美国中部及东部地区（Central and Eastern United States, CEUS）的为期一年地震危险性预测。该模型假设，基于多个不同时间窗计算得到的地震活动率将保持相对稳定，可用于2017年地震危险性与破坏强度的预测。本次评估是开发CEUS业务化地震预报的第一步，后续可结合更新后的地震活动性数据与模型参数对分析结果进行修订。共识输入模型考量了多套不同的地震目录时长、平滑参数、最大震级以及地面运动估计方案，同时涵盖了地震发生的不确定性与科学界的观点分歧。在部分活跃诱发地震区域，本次预测的地震危险性较2014年美国地质调查局国家地震危险性模型（National Seismic Hazard Model, NSHM）高出3倍以上——2014年的NSHM未纳入诱发地震的影响；而在部分已观测到诱发地震活动停止的区域，地震危险性则回归至2014年NSHM的水平。本数据集包含了经纬度间隔为0.05度的网格点的危险性曲线计算结果，代表了1年内超越概率为1%的平均修正麦加利烈度（Modified Mercalli Intensity, MMI）。该烈度值由峰值地面加速度与1秒谱响应加速度分别转换为MMI后取平均得到。数据集覆盖美国中部及东部地区，基于前文所述的一年期预测模型生成。