Understanding the seismic signature of transtensional opening in the Reykjanes peninsula rift zone, SW Iceland

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985530%3A_____%2F25%3A00603637" target="_blank" >RIV/67985530:_____/25:00603637 - isvavai.cz</a>

Výsledek na webu

<a href="https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029566" target="_blank" >https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029566</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1029/2024JB029566" target="_blank" >10.1029/2024JB029566</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Understanding the seismic signature of transtensional opening in the Reykjanes peninsula rift zone, SW Iceland

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

Understanding the seismic signature of transtensional opening in the Reykjanes peninsula rift zone, SW Iceland

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10507 - Volcanology

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Geophysical Research-Solid Earth

ISSN

2169-9313

e-ISSN

2169-9356

Svazek periodika

130

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

25

Strana od-do

e2024JB029566

Kód UT WoS článku

001387869800001

EID výsledku v databázi Scopus

2-s2.0-85215815590