Stress variations in southern Tonga slab derived from deep-focus earthquakes

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985530%3A_____%2F24%3A00585722" target="_blank" >RIV/67985530:_____/24:00585722 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216208:11310/24:10495381

Výsledek na webu

<a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023JB028039" target="_blank" >https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023JB028039</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1029/2023JB028039" target="_blank" >10.1029/2023JB028039</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Stress variations in southern Tonga slab derived from deep-focus earthquakes

Popis výsledku v původním jazyce

Tonga is a convergent plate boundary between the Pacific and Australian plates and is the fastest and the most seismically active deep subduction system in the world. We focused on southern Tonga (south of latitude 22 degrees S) and the mantle transition zone (depths of 410-670 km), where seismic activity forms two subparallel bands of events in the east and west. We performed stress analysis by inverting focal mechanisms of earthquakes available in the Global Centroid Moment Tensor catalog and revealed two distinct stress regimes in the slab. While the stress orientation in the eastern slab segment conforms to the down-dip compressional stress along the entire slab, the stress orientation in the western slab segment is different, having the maximum compression in the vertical direction. This suggests that the western segment can represent a stagnant slab with flattening and bending, as proposed by modeling studies. Its connection with the younger actively subducting slab is supported by the horizontal westward shift at 520 km depth. The stress analysis also indicates substantially different fault orientations in both segments. In the actively dipping slab, the majority of activated faults are predominantly sub-horizontal. However, they are significantly inclined from vertical in the stagnant slab segment. A higher scatter in fault orientations in the stagnant slab suggests deformation, fragmentation and rheological complexity resulting from bending and flattening.

Název v anglickém jazyce

Stress variations in southern Tonga slab derived from deep-focus earthquakes

Popis výsledku anglicky

Tonga is a convergent plate boundary between the Pacific and Australian plates and is the fastest and the most seismically active deep subduction system in the world. We focused on southern Tonga (south of latitude 22 degrees S) and the mantle transition zone (depths of 410-670 km), where seismic activity forms two subparallel bands of events in the east and west. We performed stress analysis by inverting focal mechanisms of earthquakes available in the Global Centroid Moment Tensor catalog and revealed two distinct stress regimes in the slab. While the stress orientation in the eastern slab segment conforms to the down-dip compressional stress along the entire slab, the stress orientation in the western slab segment is different, having the maximum compression in the vertical direction. This suggests that the western segment can represent a stagnant slab with flattening and bending, as proposed by modeling studies. Its connection with the younger actively subducting slab is supported by the horizontal westward shift at 520 km depth. The stress analysis also indicates substantially different fault orientations in both segments. In the actively dipping slab, the majority of activated faults are predominantly sub-horizontal. However, they are significantly inclined from vertical in the stagnant slab segment. A higher scatter in fault orientations in the stagnant slab suggests deformation, fragmentation and rheological complexity resulting from bending and flattening.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10507 - Volcanology

Projekt

<a href="/cs/project/GA22-10747S" target="_blank" >GA22-10747S: Výpočet napětí a jeho časoprostorového rozložení z ohniskových mechanismů a seismických momentových tenzorů</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

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

129

Číslo periodika v rámci svazku

5

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

17

Strana od-do

e2023JB028039

Kód UT WoS článku

001209370200001

EID výsledku v databázi Scopus

2-s2.0-85191697584