Open AccessOn the possibility of determining the focal parameters of an earthquake using a local network equipped with three-component seismometers
Author(s) -
B. Alessandrini
Publication year - 2010
Publication title -
annals of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 60
eISSN - 2037-416X
pISSN - 1593-5213
DOI - 10.4401/ag-4695
Subject(s) - seismometer , azimuth , geology , seismology , focal point , point (geometry) , component (thermodynamics) , induced seismicity , focal mechanism , geodesy , cardinal point , geometry , optics , physics , mathematics , thermodynamics
Bv exploiting the possibility of determining the angle of emergence
and the azimuth of a seismic ray at an observation point equipped with
one vertical seismograph and two horizontal ones and using recent digital
data acquisition techniques, an effective method for locating the focus
of a seismic event is proposed. By means of this method it is possible
to obtain, in addition to the point customarily considered as the "barycentre"
of the focal volume, also a quantity which represents the "convergence"
of various seismic rays on the source zone.
This method makes it possible actually to "determine" the focal parameters
and does away with the need for approximation methods of the
least squares type.
In the present investigation, tests have been carried out to determine
the accuracy of the angle of emergence and the azimuth for a number
of earthquakes, together with other theoretical tests for the relocation ot
the focal parameters using a three-dimensional crust model
and the azimuth of a seismic ray at an observation point equipped with
one vertical seismograph and two horizontal ones and using recent digital
data acquisition techniques, an effective method for locating the focus
of a seismic event is proposed. By means of this method it is possible
to obtain, in addition to the point customarily considered as the "barycentre"
of the focal volume, also a quantity which represents the "convergence"
of various seismic rays on the source zone.
This method makes it possible actually to "determine" the focal parameters
and does away with the need for approximation methods of the
least squares type.
In the present investigation, tests have been carried out to determine
the accuracy of the angle of emergence and the azimuth for a number
of earthquakes, together with other theoretical tests for the relocation ot
the focal parameters using a three-dimensional crust model