Global constraints on intermediate-depth intraslab stresses from slab geometries and mechanisms of double seismic zone earthquakes

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985530%3A_____%2F22%3A00560474" target="_blank" >RIV/67985530:_____/22:00560474 - isvavai.cz</a>

Výsledek na webu

<a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GC010498?af=R" target="_blank" >https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GC010498?af=R</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1029/2022GC010498" target="_blank" >10.1029/2022GC010498</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Global constraints on intermediate-depth intraslab stresses from slab geometries and mechanisms of double seismic zone earthquakes

Popis výsledku v původním jazyce

Double seismic zones (DSZs), parallel planes of intermediate-depth earthquakes inside oceanic slabs, have been observed in a number of subduction zones and may be a ubiquitous feature of downgoing oceanic plates. Focal mechanism observations from DSZ earthquakes sample the intraslab stress field at two distinct depth levels within the downgoing lithosphere. A pattern of downdip compressive over downdip extensive events was early on interpreted to indicate an unbending-dominated intraslab stress field. In the present study, we show that the intraslab stress field in the depth range of DSZs is much more variable than previously thought. Compiling DSZ locations and mechanisms from literature, we observe that the “classical” pattern of compressive over extensive events is only observed at about half of the DSZ locations around the globe. The occurrence of extensional mechanisms across both planes accounts for most other regions. To obtain an independent estimate of the bending state of slabs at intermediate depths, we compute (un)bending estimates from slab geometries taken from the slab2 compilation of slab surface depths. We find no clear global prevalence of slab unbending at intermediate depths, and the occurrence of DSZ seismicity does not appear to be limited to regions of slab (un)bending. Focal mechanism observations are frequently inconsistent with (un)bending estimates from slab geometries, which may imply that bending stresses are not always prevalent, and that other stress types such as in-plane tension due to slab pull or shallow compression due to friction along the plate interface may also play an important role.

Název v anglickém jazyce

Global constraints on intermediate-depth intraslab stresses from slab geometries and mechanisms of double seismic zone earthquakes

Popis výsledku anglicky

Double seismic zones (DSZs), parallel planes of intermediate-depth earthquakes inside oceanic slabs, have been observed in a number of subduction zones and may be a ubiquitous feature of downgoing oceanic plates. Focal mechanism observations from DSZ earthquakes sample the intraslab stress field at two distinct depth levels within the downgoing lithosphere. A pattern of downdip compressive over downdip extensive events was early on interpreted to indicate an unbending-dominated intraslab stress field. In the present study, we show that the intraslab stress field in the depth range of DSZs is much more variable than previously thought. Compiling DSZ locations and mechanisms from literature, we observe that the “classical” pattern of compressive over extensive events is only observed at about half of the DSZ locations around the globe. The occurrence of extensional mechanisms across both planes accounts for most other regions. To obtain an independent estimate of the bending state of slabs at intermediate depths, we compute (un)bending estimates from slab geometries taken from the slab2 compilation of slab surface depths. We find no clear global prevalence of slab unbending at intermediate depths, and the occurrence of DSZ seismicity does not appear to be limited to regions of slab (un)bending. Focal mechanism observations are frequently inconsistent with (un)bending estimates from slab geometries, which may imply that bending stresses are not always prevalent, and that other stress types such as in-plane tension due to slab pull or shallow compression due to friction along the plate interface may also play an important role.

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

2022

Kód důvěrnosti údajů

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

Název periodika

Geochemistry, Geophysics, Geosystems

ISSN

1525-2027

e-ISSN

1525-2027

Svazek periodika

23

Číslo periodika v rámci svazku

9

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

28

Strana od-do

e2022GC010498

Kód UT WoS článku

000853400200001

EID výsledku v databázi Scopus

2-s2.0-85139155226