Seismic hazard is commonly characterised using instrumental seismic records. However, these records are short relative to earthquake repeat times, and extrapolating to estimate seismic hazard can misrepresent the probable location, magnitude, and frequency of future large earthquakes. Although paleoseismology can address this challenge, this approach requires certain geomorphic setting, is resource intensive, and can carry large inherent uncertainties. Here, we outline how fault slip rates and recurrence intervals can be estimated by combining fault geometry, earthquake-scaling relationships, geodetically derived regional strain rates, and geological constraints of regional strain distribution. We apply this approach to southern Malawi, near the southern end of the East African Rift, and where, although no on-fault slip rate measurements exist, there are constraints on strain partitioning between border and intra-basin faults. This has led to the development of the South Malawi Active Fault Database (SMAFD), a geographical database of 23 active fault traces, and the South Malawi Seismogenic Source Database (SMSSD), in which we apply our systems-based approach to estimate earthquake magnitudes and recurrence intervals for the faults compiled in the SMAFD. We estimate earthquake magnitudes of M_W 5.4–7.2 for individual fault sections in the SMSSD and M_W 5.6–7.8 for whole-fault ruptures. However, low fault slip rates (intermediate estimates ∼ 0.05–0.8 mm/yr) imply long recurrence intervals between events: 10²–10⁵ years for border faults and 10³–10⁶ years for intra-basin faults. Sensitivity analysis indicates that the large range of these estimates can best be reduced with improved geodetic constraints in southern Malawi. The SMAFD and SMSSD provide a framework for using geological and geodetic information to characterise seismic hazard in regions with few on-fault slip rate measurements, and they could be adapted for use elsewhere in the East African Rift and globally.

中文翻译：

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一种基于系统的方法来对历史或仪器地震活动很少的地区的地震危险进行参数化：马拉维南部的活动断层和震源数据库

通常使用仪器地震记录来表征地震危险。但是，这些记录相对于地震重复时间而言是短的，并且推断地震危险性的推断可能会误解未来大地震的可能位置，震级和发生频率。尽管古地震学可以解决这一挑战，但这种方法需要一定的地貌背景，资源密集，并且可能存在较大的固有不确定性。在这里，我们概述了如何通过结合断层的几何形状，地震比例关系，大地测量得出的区域应变率和区域应变分布的地质约束条件来估算断层滑动率和复发间隔。我们将这种方法应用于马拉维南部，东非大裂谷南端附近，尽管那里没有断层滑移率测量，边界断层和盆地内断层之间的应变分配受到限制。这导致了南马拉维活动断层数据库（SMAFD），包含23条活动断层痕迹的地理数据库以及南马拉维发震源数据库（SMSSD）的开发，在这些数据库中，我们应用了基于系统的方法来估计地震震级以及在SMAFD中编译的故障的重复间隔。我们估计的地震烈度为 在这种方法中，我们应用基于系统的方法来估计SMAFD中编辑的断层的地震震级和重复间隔。我们估计的地震烈度为 在这种方法中，我们应用基于系统的方法来估计SMAFD中编辑的断层的地震震级和重复间隔。我们估计的地震烈度为中号_W¯¯  5.4-7.2在SMSSD和个别故障部分中号_W¯¯  5.6-7.8为全断层破裂。然而，低断层滑动速率（中间估计 〜  0.05-0.8毫米/年）暗示事件之间长复发周期：10 ² -10 ⁵ 年边界故障和10 ³ -10 ⁶ 盆地内断层的年数。敏感性分析表明，通过改善马拉维南部的大地测量约束，可以最好地减少这些估计的较大范围。SMAFD和SMSSD提供了一个框架，该框架可使用地质和大地测量信息来表征很少进行过失滑率测量的地区的地震危险，并且可以将其改编为在东非大裂谷和全球范围内使用。