@misc{10481/98664,
year = {2024},
month = {12},
url = {https://hdl.handle.net/10481/98664},
abstract = {We analyze seismicity and centroid moment tensors (CMTs) on the Reykjanes Peninsula, Iceland,
during the early phase of a widespread unrest period that led to multiple fissure eruptions between 2021 and
2024. We use a dense temporary seismic array, together with fiber‐optic distributed acoustic sensing data, and
incorporate first‐motion polarities into the CMT inversion to improve accuracy, generating a total of 300 robust
CMT solutions for magnitudes Mw>2.5, focusing on 83 reliable Mw>2.7 earthquakes for interpretation. The
CMTs predominantly exhibit shallow strike‐slip faulting, with a few normal faulting events compatible with
tectonic stress. Interestingly, significant positive isotropic components are resolved, contributing up to 15% of
the moment release. We also develop a new high‐resolution seismic catalog of 34,407 events and show that
larger shallow earthquakes at the plate boundary are preceded by the slow upward migration of
microearthquakes from below, suggesting that intruding magmatic fluids interact with the oblique plate
boundary to trigger slow slip events. We interpret our results as the seismic response to transtensional motion at
the plate boundary in the brittle upper crust under shear, in response to stress changes induced by the intrusion of
pressurized fluids in the lower crust. The complex interaction of multiple subparallel dikes with the plate
boundary fault contributes to a broader deformation band that accommodates both tectonic and magmatic
stresses. While the location and magnitude of the CMTs correlate with reactivated surface fractures and faults,
the locations of intense, deep microseismic swarms indicate the sites of future fissure eruptions.},
organization = {Projects
407141557 (LO 2505/1‐1) and 517982028
(BU 4346/1‐1) of the Deutsche
Forschungsgemeinschaft (DFG, German
Research Foundation)},
organization = {Consejería de Universidad,
Investigación e Innovación and by ERDF
Andalusia Program 2021–2027 (project C.
EXP.178. UGR23)},
organization = {Plan propio de
investigación of University of Granada,
programa de proyectos de investigación
precompetitivos de jóvenes investigadores
(project PPJIA2023.002)},
publisher = {Wiley Online Library},
keywords = {divergent plate boundaries},
keywords = {transtensional opening mechanism},
keywords = {earthquake source observations},
title = {Understanding the Seismic Signature of Transtensional Opening in the Reykjanes Peninsula Rift Zone, SW Iceland},
doi = {10.1029/2024JB029566},
author = {Büyükakpınar, Pınar and Isken, Marius Paul and Heimann, Sebastian and Dahm, Torsten and Kühn, Daniela and Starke, Juliane and López Comino, José Ángel and Cesca, Simone and Doubravová, Jana and Árni Gudnason, Egill and Ágústsdóttir, Thorbjörg},
}