ShakeMap is the tool to evaluate the ground motion effect of earthquakes in vast areas. It is useful to delimit the zones where the shaking is expected to have been most significant, for civil defense rapid response. From the earthquake engineering point of view, it can be used to infer the seismic actions on the built environment to calibrate vulnerability models or to define the reconstruction policies based on observed damage vs shaking. In the case of long-lasting seismic sequences, it can be useful to develop ShakeMap envelopes, that is, maps of the largest ground intensity among those from the ShakeMap of (selected) events of a seismic sequence, to delimit areas where the effects of the whole sequence have been of structural engineering relevance. This study introduces ShakeMap envelopes and discusses them for the central Italy 2016–2017 seismic sequence. The specific goals of the study are: (i) to compare the envelopes and the ShakeMap of the main events of the sequence to make the case for sequence-based maps; (ii) to quantify the exceedance of design seismic actions based on the envelopes; (iii) to make envelopes available for further studies and the reconstruction planning; (iv) to gather insights on the (repeated) exceedance of design seismic actions at some sites. Results, which include considerations of uncertainty in ShakeMap, show that the sequence caused exceedance of design hazard in thousands of square kilometers. The most relevant effects of the sequence are, as expected, due to the mainshock, yet seismic actions larger than those enforced by the code for structural design are found also around the epicenters of the smaller magnitude events. At some locations, the succession of ground-shaking that has excited structures, provides insights on structural damage accumulation that has likely taken place; something that is not accounted for explicitly in modern seismic design. The envelopes developed are available as supplemental material.

ShakeMap是评估大面积地震地震动效应的工具。划定预计震动最显着的区域对于民防快速反应是有用的。从地震工程的角度来看，它可用于推断建筑环境上的地震作用，以校准脆弱性模型或根据观察到的损坏与震动来定义重建策略。在长期地震序列的情况下，开发 ShakeMap 包络是有用的，即从地震序列的（选定的）事件的 ShakeMap 中绘制最大地面强度的地图，以划定受到影响的区域。整个序列都与结构工程相关。本研究介绍了 ShakeMap 包络，并针对意大利中部 2016-2017 年地震序列对其进行了讨论。该研究的具体目标是：(i) 比较序列主要事件的信封和 ShakeMap，为基于序列的地图提供理由；(ii) 根据包络线量化设计地震作用的超出；(iii) 为进一步研究和重建计划提供信封；(iv) 收集有关某些地点（重复）超过设计地震作用的见解。结果，包括对 ShakeMap 中不确定性的考虑，表明该序列导致了数千平方公里的设计危险超出。正如预期的那样，该序列最相关的影响是由于主震，然而，在较小震级事件的震中附近也发现了比结构设计规范所强制执行的地震作用更大的地震作用。在某些地点，激发结构的连续地震动提供了对可能发生的结构损伤积累的见解；在现代抗震设计中没有明确考虑的东西。开发的信封可作为补充材料。