Seismic anisotropy in the rift of the Reykjanes Peninsula, SW Iceland, calculated using a new tomographic method

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985530%3A_____%2F21%3A00545466" target="_blank" >RIV/67985530:_____/21:00545466 - isvavai.cz</a>

Výsledek na webu

<a href="https://link.springer.com/article/10.1007/s00024-021-02784-1" target="_blank" >https://link.springer.com/article/10.1007/s00024-021-02784-1</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00024-021-02784-1" target="_blank" >10.1007/s00024-021-02784-1</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Seismic anisotropy in the rift of the Reykjanes Peninsula, SW Iceland, calculated using a new tomographic method

Popis výsledku v původním jazyce

A new algorithm and computer code for seismic tomography in anisotropic inhomogeneous media was developed. The new tomographic approach is a generalization of classical isotropic seismic tomography which introduces spatially and directionally varying slowness. The velocity model was considered as a stack of homogeneous blocks in contact, with each block individually parameterized using background velocities of P- and S-waves and a set of 21 anisotropy parameters. The inverse problem was solved sequentially in five steps, using the velocity model from the previous step as the starting model for the subsequent step. These steps form a chain with increasing complexity: (1) isotropic homogeneous model, (2) isotropic velocity model with vertical velocity gradient, (3) 3-D inhomogeneous isotropic velocity model, (4) 3-D inhomogeneous model with uniform anisotropy, (5) 3-D inhomogeneous generally anisotropic model. The new algorithm was applied to real bulletin data of 18 seismic stations deployed in SW Iceland and operated favourably for the monitoring of local swarm-like seismicity. Next, the resolution, robustness and accuracy of the inversion were discussed using real and synthetic data. Real data inversion revealed a predominantly depth-dependent isotropic velocity background and additional general 3-D anisotropy. The parameterization of the medium was too flexible to allow for a reliable interpretation of the anisotropy inside the elementary blocks and a cluster analysis was applied to stabilize the inversion results. Three important clusters were identified as a result. The orientation of the anisotropy (fast and slow P-wave propagation directions) of two clusters coincided with the strike of the documented faults. The orientation of the anisotropy in the third cluster was interpreted as a consequence of the fluid dynamics around Kleifarvatn Lake. The P-wave anisotropy strength reached a value of ± 5–8%.

Název v anglickém jazyce

Seismic anisotropy in the rift of the Reykjanes Peninsula, SW Iceland, calculated using a new tomographic method

Popis výsledku anglicky

A new algorithm and computer code for seismic tomography in anisotropic inhomogeneous media was developed. The new tomographic approach is a generalization of classical isotropic seismic tomography which introduces spatially and directionally varying slowness. The velocity model was considered as a stack of homogeneous blocks in contact, with each block individually parameterized using background velocities of P- and S-waves and a set of 21 anisotropy parameters. The inverse problem was solved sequentially in five steps, using the velocity model from the previous step as the starting model for the subsequent step. These steps form a chain with increasing complexity: (1) isotropic homogeneous model, (2) isotropic velocity model with vertical velocity gradient, (3) 3-D inhomogeneous isotropic velocity model, (4) 3-D inhomogeneous model with uniform anisotropy, (5) 3-D inhomogeneous generally anisotropic model. The new algorithm was applied to real bulletin data of 18 seismic stations deployed in SW Iceland and operated favourably for the monitoring of local swarm-like seismicity. Next, the resolution, robustness and accuracy of the inversion were discussed using real and synthetic data. Real data inversion revealed a predominantly depth-dependent isotropic velocity background and additional general 3-D anisotropy. The parameterization of the medium was too flexible to allow for a reliable interpretation of the anisotropy inside the elementary blocks and a cluster analysis was applied to stabilize the inversion results. Three important clusters were identified as a result. The orientation of the anisotropy (fast and slow P-wave propagation directions) of two clusters coincided with the strike of the documented faults. The orientation of the anisotropy in the third cluster was interpreted as a consequence of the fluid dynamics around Kleifarvatn Lake. The P-wave anisotropy strength reached a value of ± 5–8%.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10507 - Volcanology

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2021

Kód důvěrnosti údajů

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

Název periodika

Pure and Applied Geophysics

ISSN

0033-4553

e-ISSN

1420-9136

Svazek periodika

178

Číslo periodika v rámci svazku

8

Stát vydavatele periodika

CH - Švýcarská konfederace

Počet stran výsledku

33

Strana od-do

2871-2903

Kód UT WoS článku

000664824700002

EID výsledku v databázi Scopus

2-s2.0-85108647619