Debris flow magnitudes: a global catalog

The episodic occurrence of debris flow events in response to stochastic precipitation and wildfire events makes hazard prediction challenging. Previous work has shown that frequency-magnitude distributions of non-fire-related debris flows follow a power law, but less is known about the distribution of post-fire debris flows. As a first step in parameterizing hazard models, we use frequency-magnitude distributions and cumulative distribution functions to compare volumes of post-fire debris flows to non-fire-related debris flows. Due to the large number of events required to parameterize frequency-magnitude distributions, and the relatively small number of post-fire event magnitudes recorded in the literature, we collected data on 73 recent post-fire events in the field. The resulting catalog of 988 debris flow events is presented as an appendix to this article. We found that the empirical cumulative distribution function of post-fire debris flow volumes is composed of smaller events than that of non-fire-related debris flows. In addition, the slope of the frequency-magnitude distribution of post-fire debris flows is steeper than that of non-fire-related debris flows, evidence that differences in the post-fire environment tend to produce a higher proportion of small events. We propose two possible explanations: 1) post-fire events occur on shorter return intervals than debris flows in similar basins that do not experience fire, causing their distribution to shift toward smaller events due to limitations in sediment supply, or 2) fire causes changes in resisting and driving forces on a package of sediment, such that a smaller perturbation of the system is required in order for a debris flow to occur, resulting in smaller event volumes.

Analysis of the prospects for updating the trade pillar of the European Union-Chile Association Agreement

The perception of the present state of trade relations with Chile is obscured by a lack of adequate understanding of its legal framework as well as of the policy behind it. This study attempts to clarify the present state of and future prospects for trade between the EU and Chile through an examination of previous agreements and the EU’s new approach to trade liberalisation. The authors agree with the large consensus existing on both the EU and Chilean sides regarding the efficacy of the Association Agreement, but note that any extension of an agreement with Chile should capture the spirit of older EU agreements rather than simply following the ‘NAFTA route’. The study also includes a comparative analysis between the EU-Chile agreement and current trade agreements being negotiated by the EU and Chile with third countries.