JGR–Solid Earth

No abstract is available for this article.

The southern portion of the eastern North American margin (SENAM) is an archetypical volcanic passive margin formed during Mesozoic rifting. How past magmatic events affect the evolution of the SENAM remains an open question of fundamental importance. To better understand this question, here we construct a high-resolution 3-D crustal velocity model from the oceanic side to the continental interior with a combination of multimodal dispersion inversion and full-waveform ambient noise tomography. Our new model reveals an oceanic-continental transitional crust over a short horizonal distance of 100–150 km across the SENAM, with a local-scale lower-than-surrounding velocity anomaly directly beneath the transitional crust. Furthermore, the new model shows three intra-crustal higher-than-average velocity anomalies beneath the SENAM continent. We suggest that the magmatism assisted the Mesozoic rifting process to form the narrow ocean-continent transitional crust along the coastline. The underplating of magma beneath the transitional crust led to a reduction of seismic velocity of the uppermost mantle. In addition, it is probable that the emplacement of the Central Atlantic Magmatic Province caused widespread magmatic intrusions within the continental crust of the SENAM, which were later solidified into intra-crustal high-velocity plutons. Our findings provide new insights into crustal modification history at the passive margin.

De-aliasing products are used in the estimation process of satellite-based gravity field computation to reduce errors from high-frequency mass variations that alias into monthly gravity fields. The latest official product is AOD1B RL07 and describes non-tidal atmosphere and oceanic mass variations at 3-hourly resolution. However, the model-based de-aliasing products are inevitably incomplete and prone to temporally and spatially correlated errors that substantially contribute to errors in the estimated gravity fields. Here, we investigate possible enhancement of current de-aliasing products by nesting a regional high-resolution atmospheric reanalysis over Europe into a global reanalysis. As further novelty we include almost mass consistent terrestrial water storage variability from a regional hydrological model nested into a global model as additional component of the de-aliasing product. While we find in agreement with earlier studies only minor contributions from increasing the temporal resolution beyond 3-hourly data, our investigations suggest that contributions from continental hydrology and from regional non-hydrostatic atmospheric modeling to sub-monthly mass variations could be relevant already for gravity fields estimated from current gravity missions. Moreover, in the context of extreme events, we find regionally contributions from additional moisture fields, such as cloud liquid water, in the order of a few mm over Europe. We suggest this needs to be taken into account when preparing data analysis schemes for future space gravimetric missions.

Mass movements and delta collapses are significant sources of tsunamis in lacustrine environments, impacting human societies enormously. Paleotsunamis studies play an essential role in understanding historical events and their consequences, along with their return periods. This study investigates a paleotsunami induced by a subaqueous mass movement during the Younger Dryas to Early Holocene transition, ca. 11,700 years ago in Lake Aiguebelette (NW Alps, France). Utilizing high-resolution seismic and bathymetric surveys associated with sedimentological, geochemical, and magnetic analyses, we uncovered a paleotsunami triggered by a seismically induced mass transport deposit. Numerical simulations of mass movement have been conducted using a visco-plastic Herschel-Bulkley rheological model and corresponding tsunami wave modeled with dispersive and nondispersive models. Our findings reveal for the first time that dispersive effects may be negligible for subaqueous landslides in a relatively small lake. This research reconstructs a previously unreported paleotsunami event and enhances our understanding of tsunami dynamics in lacustrine environments.