Collaborative research projects have a significant role in filling the knowledge gaps that are obstacles to the rigorous assessment of volcanic hazards in some locations. Research is essential to generate the evidence on which raising awareness of volcanic hazards, monitoring and early warning systems, risk reduction activities and efforts to increase resilience can be built. We report the current state of volcanic hazards research and practice in Ethiopia and on the collaborative process used in the Afar Rift Consortium project to promote awareness of volcanic hazards. Effective dissemination of findings to stakeholders and the integration of results in existing practice needs: leadership by in-country researchers, effective long-term collaboration with other researchers (e.g. international groups) and operational scientists, in addition to integration with existing programmes related to disaster risk reduction initiatives.There is an increasing need for the science-based characterisation of natural hazards to support risk assessment and disaster risk management (DRM) programmes (Alcántara-Ayala et al. 2015; United Nations Office for Disaster Risk Reduction 2015a). This need exists at local, national and global levels and requires the engagement of individuals, communities, governments and international agencies (United Nations Office for Disaster Risk Reduction 2015b). Ensuring that externally funded scientific research plays an effective and timely role in DRM at all levels requires collaboration with in-country scientists (Paton et al. 2008;Mercer et al. 2010). It also requires the generation and application of a variety of tools and products that meet the needs and expectations of users.Volcanic eruptions are one of the few natural phenomena that can have consequences at a global level. Volcanic activity can result in loss of life (~280,000 since AD 1600, Auker et al. 2013), as well as environmental, social and economic losses (e.g. Gencer 2013). However, it was not until the moderately sized eruption of the Eyjafjallajökull volcano in Iceland in 2010 caused serious disruption to air traffic across the northern hemisphere (Þorkelsson 2012) that the potential global impact from erupting volcanoes became widely acknowledged. The Eyjafjallajökull 2010 eruption accumulated about US$ 5 billion of global economic losses and adversely affected long-haul aviation, trade and travel around the world (Ragona et al. 2011).Volcanic hazards have subsequently been included in global hazards and risk initiatives, such as the Global Assessment Report (GAR; United Nations Office for Disaster Risk Reduction 2015b). The 2015 GAR (GAR15) aimed to 'promote the integration of disaster risk management into development by raising the awareness that managing risks cost less than managing disasters' (United Nations Office for Disaster Risk Reduction 2016). As a global level report, GAR15 had a coarse resolution to highlight comparable risks. Assessments at a finer resolution (national and local scales) are the responsibility of the...

The complex geological and geomorphological settings of Ethiopia, consisted of highland plateaus, escarpments, deeply dissected valleys, and flat lowlands, are results of multiple episodes of orogenesis, peneplanation, crustal up-doming, faulting, and emplacement of huge volumes of lava. The broad elevation contrast raging from about −125 m to 4550 m Above Mean Sea Level (AMSL) is an important factor in determining the climate regimes, vegetation types, and even populations’ lifestyles. In Ethiopia landslides, mostly manifested as rockfall, earth slide, debris, and mudflow, are among the major geohazard problems that immensely affects life, infrastructures, and the natural environment. They widely occur in the central, S-SW, and N-NW highland regions. This study discusses the distributions, causes, and impacts of landslides and presents a susceptibility zoning map produced applying the weighted overlay analysis method in the ArcGIS environment. For this purpose, key parameters (lithology, elevation, rainfall, slope angel, land use-land cover, and aspect) were selected and assigned weights by considering their contributions to slope failures. Correlations with inventory data have shown very good matching, where more than 90% of the observed data fall in areas categorized either as moderate, high, or very high susceptible zones, where appropriate risk assessments could be mandatory before approval of major projects.

The paper highlights the potential drawback of mapping a single geophysical property for subsurface characterization in potential engineering sites. As an exemplary case study, we present the geophysical survey conducted along the surface projection of a tunnel in the quaternary volcanic terrain of the Main Ethiopia Rift. Initially, geoelectrical mapping involving 12 Vertical Electrical Sounding (VES) and a short Electrical Resistivity Imaging (ERI) line, was carried out. The 1D geoelectric model indicates that the formation resistivity at tunnel zone varies from 50 to 500 Ω∙m. The corresponding value on 2D model, (>350 Ω∙m), is also compatible. Based on limited available geological information, the geoelectric horizon was attributed to weathered and variably saturated ignimbrite. Following unexpected encounter during excavation, refraction seismic and core drilling were carried out for additional insights. Tomographic analysis of the seismic arrival times revealed that below a depth of 45 m, (tunnel zone), the velocity substratum is marked by a range, (1200–1800 m/s). Such low velocity range is typical of unconsolidated materials and, thus, cannot rationalize the geoelectrical attribution (ignimbrite). In a joint interpretation, the likely formation that may justify the observed range of the electrical resistivity and low P-wave velocity appears to be unwelded pyroclastic deposit (volcanic ash). Eventually, core samples from the tunnel zone confirmed the presence of thick ash flow. However, the unexpected ground conditions encountered at the early phase, due to insufficient information derived from a single geophysical parameter, caused extra cost and considerable delay.

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