Constraining Early-stage Rifting Through Rapid Response to the Lake Malawi Earthquake Sequence of December 2009

该RAPID提案针对发生在东非裂谷（EAR）系统马拉维北部地区的9次5级及以上地震。这些事件极其罕见，它们的群体特征对于这个特定地区和整个EAR西部分支来说都是非常不寻常的。他们将在这些地震发生的地区部署一个由10个地震台站组成的网络，以记录进一步的主震（如果发生的话）和余震，并重新定位这些事件，以更好地约束导致它们的断层或其他地下特征。具体而言，他们将评估：(1)当前事件是否表明主要的盆地边界断层正在容纳伸展，或者伸展应变是否主要发生在主要系统上盘的次级断层上；(2)深部岩浆活动是否与事件有关。这些地震为研究早期裂谷的形变和地震成因提供了难得的重要机会。准确的余震位置需要从震中地区进行观测，而震中地区目前只有一台工作中的地震仪。快速部署是必要的。2009年12月的地震造成3人死亡，数百人受伤，数千人流离失所。与此序列相关的余震还在继续，考虑到十几个最大的地震具有群集的特征，可能还会发生额外的破坏性事件。马拉维目前监测和定位这些地震的能力非常有限；他们没有固定的国家网络，在撰写本文时，马拉维北部地区只有两个地震台站记录这些事件。pi将与马拉维地质调查局（GSM）在地震探测和定位技术方面密切合作，并与美国地质勘探局、美国国际开发署和美国大使馆合作，协调正在进行的其他外联和人道主义工作。

This RAPID proposal addresses nine earthquakes of magnitude 5 and larger that have taken place in the northern Malawi segment of the East African Rift (EAR) system. These events are extremely rare, and their swarm-like characteristics are highly unusual for this particular region and for the Western Branch of the EAR as a whole. They will deploy a network of 10 seismic stations in the region of these earthquakes to record further main shocks (if they occur) and aftershocks and to relocate these events to better constrain the fault(s) or other subsurface features that are causing them. In particular they will evaluate: (1) whether current events indicate that extension is being accommodated on the major basin-bounding border fault, or whether the extensional strain is occurring primarily on secondary faults in the hanging wall of the major system; and (2) whether deep magmatic activity is associated with the events. These earthquakes offer a rare and important opportunity to address key aspects of deformation and seismogenesis in an early stage rift. Accurate aftershock locations require observations from the epicentral region, where there is currently only one operating seismometer. A rapid deployment is necessary.The December 2009 earthquake sequence has resulted in threecasualties, hundreds of injuries and thousands of displaced people. Aftershocksassociated with the sequence continue, and given the swarm-like character of the dozen or so largest events, it is possible that additional damaging events are still to come. Malawi currently has very limited capacity to monitor and locate these earthquakes; they have no permanent national network, and as of this writing only two seismic stations are in northern Malawi region recording these events.The PIs will work closely with the Geological Survey of Malawi (GSM) in earthquake detection and location techniques, as well as with the USGS, USAID, and the US Embassy to coordinate with the other outreach and humanitarian efforts underway.