Possible role of fluids in the process of earthquake swarm generation in the West Bohemia/Vogtland seismoactive region

Špičák, Aleš; Horálek, Josef

doi:10.1016/s0040-1951(01)00099-3

Cited by 90 publications

(32 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ordered migration of earthquakes heads from south to north and was first described for the strong earthquake swarm period in 1985/1986 [ Neunhöfer and Gueth , 1989]. The same tendency was documented for 669 events during the January 1997 swarm [ Špičák and Horálek , 2001]. …”

Section: Discussionmentioning

confidence: 57%

“… Špičák and Horálek [2001] assume the existence of fluid‐induced seismicity in the investigation area from comparison of the fault plane solutions of seismic events from January 1997 near Nový Kostel with the injection‐induced microearthquakes produced in the KTB borehole at a depth of about 9 km [ Zoback and Harjes , 1997]. The similarity of the mechanisms probably reflects identical conditions during the earthquake generation process.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Isotopic evidence (³He/⁴He, of fluid‐triggered intraplate seismicity

et al. 2003

View full text Add to dashboard Cite

[1] The aim of this study is to find a link between the occurrence of mantle-derived CO 2 exhalations and earthquake swarms beneath the western Eger rift, central Europe. We monitored the gas and isotope composition of the free gas of the Eisenquelle mineral spring and the Bublak mofette weekly for 2 years. These time series include periods before, during, and after an earthquake swarm event. Shifts in d 13 C and 3 He/ 4 He were found for several months after the occurrence of the earthquake swarm on 4 and 5 December 1994. The isotopic shifts were explained by the admixture of crustal fluids released at the hypocenter to the ''permanent'' mantle volatile flux. From the beginning of the earthquake swarm, as starting point for the gas release from the hypocenter and the moment of arriving fluid with changed isotopic signature at the locations, we estimated that the fluid transport velocity in the upper crust ranges between 400 m/day near a center of CO 2 emanation (Bublak mofette) and 50 m/day in the periphery (Eisenquelle mineral spring). Fault rupture induced by the buildup of fluid overpressure in the brittle crust (associated with sealing processes surrounding the ascending channels of the permanent mantle flux) seems to be the main reason for periodic/episodic earthquake swarm activity in this area.

show abstract

Section: Discussionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Isotopic evidence (³He/⁴He, of fluid‐triggered intraplate seismicity

et al. 2003

View full text Add to dashboard Cite

show abstract

“…The fluid pools as forms of velocity and electromagnetic conductivity anomalies are found in the root zones of plate boundaries (e.g., the San Andreas fault system; Becken et al, 2008Becken et al, , 2011Kirby et al, 2014), in the middle crust beneath active faults (Hobbs et al, 2004;Matsubara et al, 2004) and beneath volcanic fields (Parsons et al, 1992;Hasegawa and Yamamoto, 1994;Kanda and Ogawa, 2014). The observations support the positive involvement of crustal fluid not only in the clustering earthquakes in active geothermal fields (Todesco et al, 2004;Giammanco et al, 2008) but also in some of the subduction-unrelated inland earthquakes (Spicak and Horalek, 2001;Hainzl, 2004;Okada et al, 2012;Yoshida et al, 2014). Despite the overall acceptance of the influence of deep seated mid-crustal fluid on triggering earthquakes, the actual form of the fluid is not well understood because, by definition, it rarely breaches the earth's surface.…”

Section: Introductionmentioning

confidence: 57%

Mid-crustal fluid related to the Matsushiro earthquake swarm (1965–1967) in northern Central Japan: Geochemical reproduction

et al. 2016

View full text Add to dashboard Cite

“…This idea is also supported by the theory of fluid presence of Špičák and Horálek (2000). However, the p s v v ratio increase with depth cannot be considered as fully proven, due to the small number and higher errors of the S-wave onset times.…”

Section: Discussionmentioning

confidence: 74%

One-Dimensional qP-Wave Velocity Model of the Upper Crust for the West Bohemia/Vogtland Earthquake Swarm Region

Málek

Horálek²,

Janský

2005

Stud Geophys Geod

View full text Add to dashboard Cite

The western part of the Bohemian Massif (West Bohemia/Vogtland region) is characteristic in the relatively frequent recurrence of intraplate earthquake swarms and in other manifestations of past-to-recent geodynamic activity. In this study we derived 1Danisotropic qP-wave model of the upper crust in the seismogenic West Bohemia/Vogtland region by means of joint inversion of two independent data sets -travel times from controlled shots and arrival times from local earthquakes extracted from the WEBNET seismograms. We derived also simple 1-D P-wave and S-wave isotropic models. Reasons for deriving these models were: (a) only simplified crustal velocity models, homogeneous half-space or 1D isotropic layered models of this region, have been derived up to now and (b) a significant effective anisotropy of the upper crust in the region which was indicated recently by S-wave splitting. Both our anisotropic qP-wave and isotropic P-and S-wave velocity models are constrained by four layers with the constant velocity gradient. Weak anisotropy for P-waves is assumed. The isotropic model is represented by 9 parameters and the anisotropic one is represented by 24 parameters. A new robust and effective optimization algorithm -isometric algorithm -was used for the joint inversion. A two-step inversion algorithm was used. During the first step the isotropic P-and S-wave velocity model was derived. In the second step, it was used as a background model and the parameters of anisotropy were sought.Our 1D models are adequate for the upper crust in the West Bohemia/Vogtland swarm region up to a depth of 15 km. The qP-wave velocity model shows 5% anisotropy, the minimum velocity in the horizontal direction corresponds to an azimuth of 170°. The isotropic model indicates the V P /V S ratio variation with depth. The difference between the hypocentre locations based on the derived isotropic and anisotropic models was found to be several hundreds of meters. K e y w o r d s : West Bohemia/Vogtland region, earthquake swarm, anisotropy, 1D velocity model, inverse problem, earthquake location Stud. Geophys. Geod., 49 (2005), 501−524 501 © 2005 StudiaGeo s.r.o., Prague J. Málek et al.

show abstract

Possible role of fluids in the process of earthquake swarm generation in the West Bohemia/Vogtland seismoactive region

Cited by 90 publications

References 20 publications

Isotopic evidence (³He/⁴He, of fluid‐triggered intraplate seismicity

Isotopic evidence (³He/⁴He, of fluid‐triggered intraplate seismicity

Mid-crustal fluid related to the Matsushiro earthquake swarm (1965–1967) in northern Central Japan: Geochemical reproduction

One-Dimensional qP-Wave Velocity Model of the Upper Crust for the West Bohemia/Vogtland Earthquake Swarm Region

Contact Info

Product

Resources

About

Possible role of fluids in the process of earthquake swarm generation in the West Bohemia/Vogtland seismoactive region

Cited by 90 publications

References 20 publications

Isotopic evidence (3He/4He, of fluid‐triggered intraplate seismicity

Isotopic evidence (3He/4He, of fluid‐triggered intraplate seismicity

Mid-crustal fluid related to the Matsushiro earthquake swarm (1965–1967) in northern Central Japan: Geochemical reproduction

One-Dimensional qP-Wave Velocity Model of the Upper Crust for the West Bohemia/Vogtland Earthquake Swarm Region

Contact Info

Product

Resources

About

Isotopic evidence (³He/⁴He, of fluid‐triggered intraplate seismicity

Isotopic evidence (³He/⁴He, of fluid‐triggered intraplate seismicity