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Natural Hazards

When nature strikes with force, the effects can be devastating. It is critically important to better study and understand natural hazards to help mitigate against their effects. In this collection, we focus on geological hazards such as volcanic eruptions, tectonic earthquakes and mass movements.

Editorials

Interacting geological processes can cause complex hazard cascades that threaten life and property. Past events are instructive, but physical understanding must be paired with effective communication to minimize the risks posed by these events.

Editorial | | Nature Geoscience

Volcanic Hazards

The unprecedented cost of the 2018 eruption in Hawai’i reflects an intersection of disparate physical and social phenomena: widely spaced, highly destructive eruptions, and atypically high population growth. These were linked and the former indirectly drove the latter with unavoidable consequences.

Comment | Open Access | | Nature Communications

This review dives deep into how earthquakes affect volcanoes, specifically into the relation between tectonic seismic activity and subsequent eruptions. Activity may increase in any volcanic setting in the 2–5 years following an earthquake, and especially at volcanic centres featuring vigorous hydrothermal activity.

Review Article | Open Access | | Nature Communications

Pyroclastic density currents are complex multiphase flows originating from volcanic eruptions and account for almost a third of volcanic fatalities globally. This Review discusses recent advances in understanding of the complex internal processes within pyroclastic density currents and how these influence the flow dynamics and hazard footprints.

Review Article | | Nature Reviews Earth & Environment

The authors here present geodetic and seismic data for a complete eruptive cycle (2005-2018) for Sierra Negra volcano, Galapagos Island. The data shows the largest pre-eruptive inflation (6.5 m) and rates of seismicity ever observed before a basaltic eruption and provides a rare illustration of caldera resurgence mechanisms.

Article | Open Access | | Nature Communications

In this study, the authors investigate the predictability of sudden eruptions, motivated by the 2019 eruption at Whakaari (White Island), New Zealand. The paper proposes a machine learning approach that is able to identify eruption precursors in data streaming from a single seismic station at Whakaari.

Article | Open Access | | Nature Communications

Here, the authors use 20 years of ground deformation data from Stromboli and correlate this data with eruptive records. They find that duration and amplitude of the inflation trend scales with eruption magnitude, indicating that explosive dynamics obeys the same (scale-invariant) conduit process.

Article | Open Access | | Nature Communications

Seismic Hazards

The processes leading to large earthquakes remain enigmatic. Using detailed seismic and geodetic data, this Review examines how tectonic deformation and evolving fault behaviour initiate large earthquakes, and proposes an integrated model accounting for the diversity of observations.

Review Article | | Nature Reviews Earth & Environment

The authors here present a deep learning method to determine the source focal mechanism of earthquakes in realtime. They trained their network with approximately 800k synthetic samples and managed to successfully estimate the focal mechanism of four 2019 Ridgecrest earthquakes with magnitudes larger than Mw 5.4.

Article | Open Access | | Nature Communications

The authors here present a deep learning model that simultaneously detects earthquake signals and measures seismic-phase arrival times. The model performs particularly well for cases with high background noise and the challenging task of picking the S wave arrival.

Article | Open Access | | Nature Communications

The authors show that seismogenic faults can be activated by stress perturbations by all possible modes of slip independently of the frictional properties. They demonstrate, that the nature of seismicity is mostly governed by the initial stress level along the faults.

Article | Open Access | | Nature Communications

Changes in the average size distribution of earthquakes are used to discriminate between foreshocks and aftershocks, and a traffic light classification is proposed for the real-time assessment of the probability of a subsequent larger event.

Article | | Nature

Landslides and Mass Movements

Some landslides creep at low velocities of a few millimetres to metres per year, forced by external factors such as rainfall, snowmelt, earthquakes or anthropogenic forcings. This Review discusses the recent advances in understanding slow-moving landslides and examines circumstances where slow-moving landslides can accelerate and fail catastrophically.

Review Article | | Nature Reviews Earth & Environment

This study investigates the relation between El Nino and landslide impacts. The authors show how El Nino and La Nina can cause swings in exposure of population to landslides that are as large as those due to rainy-season/dry-season variability in key locations, particularly South America.

Article | Open Access | | Nature Communications

On 22 December 2018, the western flank of Anak Krakatau collapsed into the sea of the Sunda Strait triggering a tsunami which killed approximately 430 people and displaced 33,000. Here, the authors show that Anak Krakatau exhibited an elevated state of activity several months prior to the collapse, including precursory thermal anomalies, an increase in the island’s surface area, and a gradual seaward motion of the southwestern flank.

Article | Open Access | | Nature Communications

The authors here present a multi-lake paleoseismological approach to evaluate the role of earthquakes in causing a spatio-temporal cluster of large, prehistoric rockslides between 3000 and 4200 years ago in the Eastern European Alps and for which the triggering mechanisms are still debated.

Article | Open Access | | Nature Communications