We present new U–Pb age data to provide insights into the source of sediment for the Molasse Sedimentary Basin in Switzerland. The paper aims to help shed light on the processes that built the Central Alpine Mountains between ~35 and ~15 Ma. A primary conclusion drawn from the results is that at ~21 Ma there was a significant change in the sediment sources for the basin. We feel this change indicates major tectonic changes within the Central Alps.
Pangea was assembled during Devonian to early Permian times and resulted in a large-scale and winding orogeny that today transects Europe, northwestern Africa, and eastern North America. This orogen is characterized by an S shape corrugated geometry in Iberia. This paper presents the advances and milestones in our understanding of the geometry and kinematics of the Central Iberian curve from the last decade with particular attention paid to structural and paleomagnetic studies.
We propose a new exploration of the concept of spontaneous lithospheric collapse at a transform fault (TF) by performing a large study of conditions allowing instability of the thicker plate using 2-D thermomechanical simulations. Spontaneous subduction is modelled only if extreme mechanical conditions are assumed. We conclude that spontaneous collapse of the thick older plate at a TF evolving into mature subduction is an unlikely process of subduction initiation at modern Earth conditions.
In this paper, we outline the key insights from decision-making research about how, when faced with uncertainty, humans constrain decisions through the use of heuristics (rules of thumb), making them vulnerable to systematic and suboptimal decision biases. We also review existing strategies to debias decision-making that have applicability in the geosciences, giving special attention to strategies that make use of information technology and artificial intelligence.
The dolomitized intervals of the Lower Jurassic deposits exposed in the Montagna dei Fiori Anticline (Central Apennines, Italy) have been investigated. Accordingly, two fault-related dolomitization events were recognised and interpreted as having occurred before and during the Apenninic orogeny. The analyses suggest significant involvement of evaporitic fluids in both events, most likely derived from the underlying Upper Triassic Burano Formation in the detachment level.
To meet the goal of the Paris Agreement to limit temperature increase below 2 ºC, geologic carbon storage (GCS) will be necessary at the gigatonne scale. But to successfully deploy GCS, seismicity induced by CO2 injection should be controlled and maintained below a threshold that does not generate nuisances to the population. We conclude that felt induced seismicity can be minimized provided that a proper site characterization, monitoring and pressure management are performed.
Marco Cuffaro, Andrea Billi, Sabina Bigi, Alessandro Bosman, Cinzia G. Caruso, Alessia Conti, Andrea Corbo, Antonio Costanza, Giuseppe D'Anna, Carlo Doglioni, Paolo Esestime, Gioacchino Fertitta, Luca Gasperini, Francesco Italiano, Gianluca Lazzaro, Marco Ligi, Manfredi Longo, Eleonora Martorelli, Lorenzo Petracchini, Patrizio Petricca, Alina Polonia, and Tiziana Sgroi
The Ionian Sea in southern Italy is at the center of active convergence between the Eurasian and African plates, with many known
Mw > 7.0 earthquakes. Here, a recently discovered mud volcano (called the Bortoluzzi Mud Volcano or BMV) was surveyed during the Seismofaults 2017 cruise (May 2017). The BMV is the active emergence of crustal fluids probably squeezed up during the seismic cycle. As such, the BMV may potentially be used to track the seismic cycle of active faults.
Subrosion, i.e. the underground leaching of soluble rocks, causes disastrous sinkhole events worldwide. We investigate the accompanying mass transfer using quarter-yearly time-lapse gravity campaigns over 4 years in the town of Bad Frankenhausen, Germany. After correcting for seasonal soil water content, we find evidence of underground mass loss and attempt to quantify its amount. This is the first study of its kind to prove the feasibility of this approach in an urban area.
Recent seismological observations clarified that the velocity structure of the crust and upper mantle is randomly heterogeneous. I compile reported power spectral density functions of random velocity fluctuations based on various types of measurements. Their spectral envelope is approximated by the third power of wavenumber. It is interesting to study what kinds of geophysical processes created such a power-law spectral envelope at different scales and in different geological environments.
On 3 September 2017 official channels of the Democratic People’s Republic of
Korea announced the successful test of a nuclear device. This study provides a
multi-technology analysis of the 2017 North Korean event and its aftermath using a wide array of geophysical methods (seismology, infrasound, remote sensing, radionuclide monitoring, and atmospheric transport modeling). Our results clearly indicate that the September 2017 North Korean event was in fact a nuclear test.
Successive earthquakes on a single fault are not perfectly periodic in time. There is some natural random variability. This leads to variations in estimated fault slip rates over short timescales though the longer-term mean slip rate stays constant, which may cause problems when comparing slip rates at different timescales. This paper is the first to quantify these effects, demonstrating substantial variation in slip rates over a few to tens of earthquakes, but much less at longer timescales.
In this modeling study, we investigate rock uplift at plate corners (syntaxes). These are characterized by a unique bent geometry at subduction zones and exhibit some of the world's highest rock uplift rates. We find that the style of deformation changes above the plate's bent section and that active subduction is necessary to generate an isolated region of rapid uplift. Strong erosion there localizes uplift on even smaller scales, suggesting both tectonic and surface processes are important.
Fragmentation of continents often involves obliquely rifting segments that feature a complex three-dimensional structural evolution. Here we show that more than ~ 70 % of Earth’s rifted margins exceeded an obliquity of 20° demonstrating that oblique rifting should be considered the rule, not the exception. This highlights the importance of three-dimensional approaches in modelling, surveying, and interpretation of those rift segments where oblique rifting is the dominant mode of deformation.
I present the GHOST (Geoscientific Hollow Sphere Tessellation) software which allows for the fast generation of computational meshes in hollow sphere geometries counting up to a hundred million cells. Each mesh is composed of concentric spherical shells made of quadrilaterals or triangles. I focus here on three commonly used meshes used in the geodynamics/geophysics community and further benchmark the gravity and gravitational potential procedures in the simple case of a constant density.
A balanced cross section across the hypocentre of the 2017 Iran–Iraq Mw 7.3 earthquake is presented. The structural style of the area is characterised by inversion tectonics with partial decoupling between the basement and the 10 km thick sedimentary cover. The main shock is located along a low-dipping lateral ramp of the Mountain Front Fault. The balanced cross section indicates that the Mountain Front Fault is the only fault where an Mw 7.3 earthquake may occur.
Valentin Samuel Gischig, Joseph Doetsch, Hansruedi Maurer, Hannes Krietsch, Florian Amann, Keith Frederick Evans, Morteza Nejati, Mohammadreza Jalali, Benoît Valley, Anne Christine Obermann, Stefan Wiemer, and Domenico Giardini
This study shows the need for a symbiotic relationship between government and research groups for efficient management of geologic data in urban environments. Through its implementation, both the city administration and private companies benefit from the feedback of geologic knowledge acquired during this process, thereby substantially reducing the cost of construction projects and facilitating the development of aquifer management plans.
The period between 1991 and 2005 was a time when many western geologists came to the Urals to get a closer look at this famous and extraordinarily rich region. The main reason was an openness policy of the USSR government, when foreigners were admitted to this area that was formerly almost closed. The co-operation of the western geologists with local specialists was very fruitful. The author aimed to describe the most interesting findings in Uralian geology after the learned guests left.
This paper presents the results of two experiments of revegetation techniques in context of water erosion and mountainous Mediterranean climate. We studied the interest of a wood chip amendment, applied on soil surface (mulch), and its interaction with plant development. The use of different plant species and the monitoring on three growing seasons (with climatic variations) allow us to specify the interest of wood chip mulch to improve revegetation especially in erosion and drought conditions.
Salt archives in sediments are critical to understanding a number of geochemical processes in the earth surface conditions. This study presents a physical and geochemical survey into aeolian salts in the Chinese deserts to explore their possible climatic implications. The results suggest the aeolian salts are atmospheric origin without local geological limits. It is a latent indicator in onefold depositional environment but not so in diverse conditions. Palaeoenvironmental use should be careful.
We integrated fish-scale pits with mulching to test whether this integration could improve soil water conservation. The results showed that integrating fish-scale pits with mulching could conserve significantly more soil water by increasing infiltration and decreasing evaporation, and showed greater soil water storage and degree of soil water compensation compared to fish-scale pits alone. In addition, jujube branches exerted better mulching effects than maize straw.
Rocky Mountain National Park is one of the most visited national parks in the United States. 95 % of the park is managed as wilderness. This paper examines the impacts of trampling on the vegetation and soil along selected trails. Trail widening and soil loss are the most visible types of trail degradation. Insights into the influence of different factors (use level, topography) can lead to the selection of appropriate management measures to avoid or minimize negative consequences.
Following the application of organic amendment treatments, the increased organic carbon and total porosity values, as compared to the control treatment, were greater in the loamy sand soil than in the clay loam soil. Moreover, compared to the microbial respiration of control plots, the application of municipal solid waste resulted in higher levels of microbial respiration from the clay loam soil than from the loamy sand soil, whereas the reverse was found for alfalfa residue.
New stratigraphical, structural, geochemical, and geochronological data from the northern Caribbean orogenic belt indicate that the Imbert Fm constitutes a coarsening-upward stratigraphic sequence that records the transition of the sedimentation from a pre-collisional forearc to a syn-collisional piggy-back basin in the lower-to-middle Eocene. This piggy-back basin was transported to the top of the Puerto Plata ophiolitic slab as it was emplaced onto the North America continental margin units.
We compute a velocity model of the crust and uppermost mantle of southern North America, Mexico and the Caribbean. We use a recent technique based on "ambient noise" (or continuous seismic records) and a traditional one using earthquakes. Both techniques, together with the increased number of seismic stations in the region, allow us to obtain greater resolution than previous works. Some of its applications are to localize regional earthquakes and simulate ground motions.