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Data collected during well-observed eruptions can lead to dramatic increases in our understanding of volcanic processes. However, the necessary prioritization of public safety and hazard mitigation during a crisis means that scientific opportunities may be sacrificed. Thus, maximizing the scientific gains from eruptions requires improved planning and coordinating science activities among governmental organizations and academia before and during volcanic eruptions. One tool to facilitate this coordination is a Scientific Advisory Committee (SAC). In the USA, the Community Network for Volcanic Eruption Response (CONVERSE) has been developing and testing this concept during workshops and scenario-based activities. The December 2020 eruption of Kīlauea volcano, Hawaii, provided an opportunity to test and refine this model in real-time and in a real-world setting. We present here the working model of a SAC developed during this eruption. Successes of the Kīlauea SAC (K-SAC) included broadening the pool of scientists involved in eruption response and developing and codifying procedures that may form the basis of operation for future SACs. Challenges encountered by the K-SAC included a process of review and facilitation of research proposals that was too slow to include outside participation in the early parts of the eruption and a decision process that fell on a small number of individuals at the responding volcano observatory. Possible ways to address these challenges include (1) supporting community-building activities between eruptions that make connections among scientists within and outside formal observatories, (2) identifying key science questions and pre-planning science activities, which would facilitate more rapid implementation across a broader scientific group, and (3) continued dialog among observatory scientists, emergency responders, and non-observatory scientists about the role of SACs. The SAC model holds promise to become an integral part of future efforts, leading in the short and longer term to more effective hazard response and greater scientific discovery and understanding.

Continental rifts begin and develop through repeated episodes of faulting and magmatism, but strain partitioning between faulting and magmatism during discrete rifting episodes remains poorly documented. In highly evolved rifts, tensile stresses from far-field plate motions accumulate over decades before being released during relatively short time intervals by faulting and magmatic intrusions (1-3). These rifting crises are rarely observed in thick lithosphere during the initial stages of rifting. Here we show that most of the strain during the July-August 2007 seismic crisis in the weakly extended Natron rift, Tanzania, was released aseismically. Deformation was achieved by slow slip on a normal fault that promoted subsequent dyke intrusion by stress unclamping. This event provides compelling evidence for strain accommodation by magma intrusion, in addition to slip along normal faults, during the initial stages of continental rifting and before significant crustal thinning., In July-August 2007, a seismo-magmatic crisis in the Natron basin (Fig. 1) was accompanied by the first dyking event ever captured geodetically in a continental rift (4). The < 5-Myr-old [...]

Earthquake source parameter determination is of great importance for hazard assessment, as well as for a variety of scientific studies concerning regional stress and strain release and volcano-tectonic interaction. This is especially true for poorly instrumented, densely populated regions such as encountered in Africa, where even the distribution of seismicity remains poorly documented. In this paper, we combine data from satellite radar interferometry (InSAR) and teleseismic waveforms to determine the source parameters of the M 5.9 earthquake that occurred on 2008 February 3 near the cities of Bukavu (DR Congo) and Cyangugu (Rwanda). This was the second largest earthquake ever to be recorded in the Kivu basin, a section of the western branch of the East African Rift (EAR). This earthquake is of particular interest due to its shallow depth and proximity to active volcanoes and Lake Kivu, which contains high concentrations of dissolved carbon dioxide and methane. The shallow depth and possible similarity with dyking events recognized in other parts of EAR suggested the potential association of the earthquake with a magmatic intrusion, emphasizing the necessity of accurate source parameter determination. In general, we find that estimates of fault plane geometry, depth and scalar moment are highly consistent between teleseismic and InSAR studies. Centroid-moment-tensor (CMT) solutions locate the earthquake near the southern part of Lake Kivu, while InSAR studies place it under the lake itself. CMT solutions characterize the event as a nearly pure double-couple, normal faulting earthquake occurring on a fault plane striking 350° and dipping 52° east, with a rake of -101°. This is consistent with locally mapped faults, as well as InSAR data, which place the earthquake on a fault striking 355° and dipping 55° east, with a rake of -98°. The depth of the earthquake was constrained by a joint analysis of teleseismic P and SH waves and the CMT data set, showing that the earthquake occurred in the shallow crust, at approximately 8 km depth. Inversions of ENVISAT (Environment Satellite) and ALOS (Advanced Land Observation Satellite) data place the earthquake at 9 km. A comparison of the scalar moment (9.43 ± 0.06 × 10 Nm from seismology and 8.99 ± 0.010 × 10 Nm from the joint InSAR solution) shows good agreement between the two data sets. Such an agreement is in contrast to the large discrepancies observed (up to an order of magnitude) in other places along the EAR where similar earthquake sequences are associated with magmatic intrusion. From this, we infer that the rupture was brittle and occurred with little aseismic deformation as might be expected from magma injection. Our results provide insights into the style of rifting occurring in the South Kivu Volcanic Province and hence will aid future studies on seismic risk in the context of Lake Kivu and underline the importance of systematic monitoring of the EAR area. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Systems for image acquisition have revolutionized the study and monitoring of volcanic activity where field access is complex or impossible. Through a series of 3 examples in the Virunga Volcanic Province (Eastern Democratic Republic of Congo), the present work shows how times-series of photogrammetric products (i.e., point clouds, digital elevation models and orthophotos) allow the detection, quantification and interpretation of topographic changes associated with ground deformation, lava accumulation and erosion processes in volcanic craters. All these case studies of applied 4D photogrammetry also illustrate the solutions found to compensate the lack of ground control points and adapt the image acquisition strategies to the complexity of such a tropical volcanic environment.The two first examples focus on the summit crater of Nyiragongo. (1) The low level of the Nyiragongo's persistent lava lake observed during the 2012-2015 period was accompanied with the subsidence of the surrounding platform and the appearance of ring fissures. This subsidence was also detected using SAR interferometry. The modelling of that subsidence points towards a shallow source associated with the 2002-2012 accumulation of lava in the crater due to lava lake overflows. (2) On February 29, 2016, at the same time as the rise of the lava lake level, a new eruptive vent developed east of the lava lake, producing lava flows that accumulated in the crater and, for some of them, felt into the lava lake. From March 2016 to March 2018, at least 10.5 106 m3 of lava accumulated in the Nyiragongo crater, according to the comparison of digital elevation models. This volume corresponds to half of the lava flow volume emitted during the last disastrous flank eruption of the volcano, in January 2002.The final example concerns Nyamulagira volcano, where the collapse and enlargement of the pit crater located in the summit caldera was followed by the appearance of lava fountains in April and June-September 2014, and the development of a new intermittent lava lake activity starting from November 2014. From June 2014 to October 2018, about 19 106 m3 of lava accumulated in the pit crater. This summit activity at Nyamulagira seems to have inhibited the occurrence of flank eruptions, which used to occur every 1-4 years between 1938 and 2012. [ABSTRACT FROM AUTHOR]