Morfología Fluvial.-Funcionamiento de la rambla de Nogalte (Murcia) durante avenidas. Implicaciones para la cartografía de peligrosidad por riesgo de avenidas

ABSTRACT Discharge data obtained for the Rambla de Nogalte ephemeral stream by means of hydrologic modelling are low in relation to the discharge that was estimated for the 1973 catastrophic flood event. Watershed characteristics such as an elongated morphology, long stream and moderate slope defining a high concentration time do not favour either large discharge. The reason for it might be the high load attained on the 1973 flood not taken in account for the ordinary hydrologic modelling and the lack of flow evacuation capacity of the aggrading alluvial fan system at the stream mouth

Identification and Management of Indirect Volcanic Risks: Citizens’ Rockfall Observatory on the Island of El Hierro

[EN] Secondary volcanic hazards (SVH) are not usually considered in volcanic hazard analysis, nor are they specifically included in volcanic risk management plans. However, SVH may cause more damage than primary volcanic hazards (PVH). The magmatic unrest on El Hierro Island in 2011–2012 is a perfect example of how SVH can be one of the leading causes of damage during magmatic unrest. Rockfalls are common on the island of El Hierro, mainly controlled by the heterogeneous lithology and the steep topography. Heavy rainfall and strong wind are usually the main triggering factors. However, during the 2011–2012 El Hierro Island magmatic unrest most of them were triggered due to earthquakes. Rock falls caused roadblocks and damage to road infrastructure. Two reports analysing rockfall hazards and associated risks during the emergency were based on expert knowledge and highlighted the need for, a comprehensive inventory of rockfalls, their processes characterisation, recurring event timing estimations and an analysis of their triggering factors. The need for better rockfall understanding on El Hierro island and the extensive experience of the local Civil Protection agents that were already working with citizens during the volcanic emergency, led to the development of a Rockfall Citizen’s Observatory. The observatory aims to engage citizens in the study of this geological hazard, hence providing a substantial increase in the amount of high quality data for rockfall risk analysis.Peer reviewe