Single-station estimates of the focal mechanism for weak earthquakes

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985530%3A_____%2F23%3A00568864" target="_blank" >RIV/67985530:_____/23:00568864 - isvavai.cz</a>

Výsledek na webu

<a href="https://pubs.geoscienceworld.org/ssa/srl/article/94/2A/944/619557/Single-Station-Estimates-of-the-Focal-Mechanism" target="_blank" >https://pubs.geoscienceworld.org/ssa/srl/article/94/2A/944/619557/Single-Station-Estimates-of-the-Focal-Mechanism</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1785/0220220096" target="_blank" >10.1785/0220220096</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Single-station estimates of the focal mechanism for weak earthquakes

Popis výsledku v původním jazyce

The focal mechanism is a parameter of an earthquake that typically demands observa-tions surrounding the focus. If such observations are not available, only limited infor-mation can be retrieved regarding the process of rupturing (e.g., geometry, and the orientation of the fault plane and slip), not its shear versus non-shear nature. In extreme cases of monitoring that incorporate a single station, a mechanism can only be esti-mated if data from additional seismic phases are available. However, such is not the case for weak seismic events, in which a station often only records direct P and S waves. Under such conditions, information is severely limited, and standard synthetics-to-data-matching does not allow even the simplest and most constrained seismological source model, namely a double-couple focal mechanism, to be determined. During data review, we detected an internal ambiguity for solutions of the inverse task using sin-gle-station geometry. Nevertheless, we found that at least some important features of a focal mechanism may be retrieved. Such scenarios occur for particular configurations of focal mechanism orientation and source-station direction, as follows: (1) If a station lies in a direction within the quadrant of compressions, the Taxis can be retrieved with reasonable error. However, the P axis remains ambiguous. (2) Conversely, if a station lies in a direction within the quadrant of dilatations, reasonable resolution of the P axis is possible, while the T axis remains ambiguous. (3) If the data are noisy, apart from extreme cases of contamination, the possibility of estimating the direction of the T/P axis remains intact. The closer source-station direction is to the center of the quadrant of compressions or dilatations, the better the resolution of the T/P axis. Our method was applied to selected weak earthquakes recorded by the three-component borehole seis-mic station MDBI, located near the Dead Sea in Israel.

Název v anglickém jazyce

Single-station estimates of the focal mechanism for weak earthquakes

Popis výsledku anglicky

The focal mechanism is a parameter of an earthquake that typically demands observa-tions surrounding the focus. If such observations are not available, only limited infor-mation can be retrieved regarding the process of rupturing (e.g., geometry, and the orientation of the fault plane and slip), not its shear versus non-shear nature. In extreme cases of monitoring that incorporate a single station, a mechanism can only be esti-mated if data from additional seismic phases are available. However, such is not the case for weak seismic events, in which a station often only records direct P and S waves. Under such conditions, information is severely limited, and standard synthetics-to-data-matching does not allow even the simplest and most constrained seismological source model, namely a double-couple focal mechanism, to be determined. During data review, we detected an internal ambiguity for solutions of the inverse task using sin-gle-station geometry. Nevertheless, we found that at least some important features of a focal mechanism may be retrieved. Such scenarios occur for particular configurations of focal mechanism orientation and source-station direction, as follows: (1) If a station lies in a direction within the quadrant of compressions, the Taxis can be retrieved with reasonable error. However, the P axis remains ambiguous. (2) Conversely, if a station lies in a direction within the quadrant of dilatations, reasonable resolution of the P axis is possible, while the T axis remains ambiguous. (3) If the data are noisy, apart from extreme cases of contamination, the possibility of estimating the direction of the T/P axis remains intact. The closer source-station direction is to the center of the quadrant of compressions or dilatations, the better the resolution of the T/P axis. Our method was applied to selected weak earthquakes recorded by the three-component borehole seis-mic station MDBI, located near the Dead Sea in Israel.

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

2023

Kód důvěrnosti údajů

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

Název periodika

Seismological Research Letters

ISSN

0895-0695

e-ISSN

1938-2057

Svazek periodika

94

Číslo periodika v rámci svazku

2A

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

17

Strana od-do

944-960

Kód UT WoS článku

000944198000005

EID výsledku v databázi Scopus

2-s2.0-85151039800