Moment‐tensor analysis using regional data: Application to the 25 March, 1993, Scotts Mills, Oregon, Earthquake

Nábělek, J.; Xia, Ganyuan

doi:10.1029/94gl02760

Cited by 75 publications

(46 citation statements)

References 10 publications

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“…Since then, SMT inversion has been carried out increasingly routinely using teleseismic recordings of intermediate-to large-magnitude earthquakes. The recent introduction of modern broadband digital regional networks has made it possible to develop SMT inversion techniques for smallermagnitude earthquakes at regional distances (Dreger and Helmberger, 1993;Romanowicz et al, 1993;Nabelek and Xia, 1995;Randall et al, 1995;Thio and Kanamori, 1995;Ammon et al, 1998).…”

Section: Introductionmentioning

confidence: 96%

Near-real-time Seismic Moment-tensor Determination in Spain

Rueda¹,

Mézcua²

2005

Seismological Research Letters

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Section: Introductionmentioning

confidence: 96%

Near-real-time Seismic Moment-tensor Determination in Spain

Rueda¹,

Mézcua²

2005

Seismological Research Letters

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“…It is applied to teleseismic records routinely (e.g., DZIEWONSKI et al, 1981;SIPKIN and ZIRBES, 1997), and to long-period regional data (e.g., PAPAZACHOS et al, 1991;BRAUNMILLER et al, 1994BRAUNMILLER et al, , 1995BRAUNMILLER et al, , 2002NABELEK and XIA, 1995;LOUVARI et al, 2001;KUBO et al, 2002). Application to short-period regional and local data is less frequent due to problems with construction of reliable high-frequency Green's function (e.g., TEYSSONEYRE et al, 2002;SˇI´LENY´and HOFSTETTER, 2002;BUFORN and COCA, 2002), but waveform modeling is important here because from weak earthquakes a small number of records is usually available, Figure 1 The study region: tectonic units and location of epicenters and seismic stations.…”

Section: Introductionmentioning

confidence: 99%

Source Parameters of Weak Crustal Earthquakes of the Vrancea Region from Short-period Waveform Inversion

Ardeleanu

Rădulian

Šı́lený

et al. 2005

Pure appl. geophys.

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High-frequency records of nine low magnitude shallow earthquakes of the Vrancea (Romania) seismic region are inverted for the seismic moment tensor (MT). An approach is suggested regarding how to obtain at least a rough estimate of the MT when the information on the structure of the crust is poor. Here simple 1-D layered models are used in the Green's function synthesis despite the fact that the structure of the region is undoubtedly very complex. Different 1-D models were used for different source-station paths to approximate lateral variations. Record of a station located on a ray path which crosses a structure differing substantially from a 1-D model may however bias the retrieved MT essentially. Therefore, we did not collectively process all records, but subsets of stations separately. We check the consistency of the MTs resulting from these individual ''bootstrap'' solutions, and reject those which differ substantially, assuming that this is due to the oversimplification of the forward modeling. Thereafter, the averaged moment tensor yielded by the consistent subsets is accepted. Moreover, the distribution of the T, N and P axes from the moment tensors used for averaging provides a rough estimate of their reliability.Following this simplistic procedure, we found seven acceptably constrained solutions among nine events processed. Their P axes are compared with the general trend of the stress in the area: three comply with it, the others should be attributed to the complex stress field active in the region.

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“…Regional moment tensor solutions are currently computed in near-real time using a variety of methods (Dreger and Helmberger, 1993;Romanowicz et al, 1993;Nabelek and Xia, 1995;Randall et al, 1994;Thio and Kanamori, 1995;Ammon et al, 1998). Pasyanos and Romanowicz (1996), Fukuyama et al (1998), Bernardi et al (2004), and Rueda and Mezcua (2005) document the real-time implementation of some of these methods.…”

Section: Introductionmentioning

confidence: 99%

An Evaluation of the SCSN Moment Tensor Solutions: Robustness of the Mw Magnitude Scale, Style of Faulting, and Automation of the Method

Clinton¹,

Hauksson²,

Solanki³

2006

Bulletin of the Seismological Society of America

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We have generated moment tensor solutions and moment magnitudes (M w ) for Ͼ1700 earthquakes of local magnitude (M L ) Ͼ3.0 that occurred from September 1999 to November 2005 in southern California. The method is running as an automated real-time component of the Southern California Seismic Network (SCSN), with solutions available within 12 min of event nucleation. For local events, the method can reliably obtain good-quality solutions for M w with M L Ͼ3.5, and for the moment tensor for events with M L Ͼ4.0. The method uses the 1D Time-Domain INVerse Code (TDMT_INVC) software package (Dreger, 2003). The Green's functions have been predetermined for various velocity profiles in southern California, which are used in the inversion of observed three-component broadband waveforms (10-100 sec), using data from at least four stations. Moment tensor solutions have an assigned quality factor dependent on the number of stations in the inversion, and the goodness of fit between synthetic and observed data. If a minimum quality factor is attained, the M L or M w is 5.0 or greater, and if the event is in the southern California reporting regions, the M w will be the official SCSN/CISN magnitude.The M w from the high-quality solutions determined from our method generally correlate very well with reviewed M L , except in regions at the perimeter of the network. The M w reported here indicates the SCSN M L systematically underestimates the magnitude in the Mexicali region of Baja California, Mono Lakes area, Coso region, and the Brawley seismic zone, and overestimates the magnitude in the Coastal Ranges.Comparisons of the moment tensors determined using this model are made with Harvard Centroid Moment Tensors generated for larger earthquakes in the California region, and recent 3D models for events in the Los Angeles region, with excellent correlation.Most of the earthquakes with good-quality solutions exhibit strike-slip faulting, in particular, along the major late Quaternary strike-slip faults. Thrust faulting on eastwest-striking planes is observed along the southern edge of the Transverse Ranges, while northwest-striking thrust faulting is observed in the Coastal Ranges. Normal faulting is most common in Baja California and southern Sierra Nevada including the western Basin and Range region.Poor-quality solutions with unreliable M w are caused by excessive background noise in the waveforms. Small events (M L Ͻ 4.0) can be affected by ambient noise or teleseisms, but larger events can also have unreliable solutions if they follow a recent large regional event.

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Moment‐tensor analysis using regional data: Application to the 25 March, 1993, Scotts Mills, Oregon, Earthquake

Cited by 75 publications

References 10 publications

Near-real-time Seismic Moment-tensor Determination in Spain

Near-real-time Seismic Moment-tensor Determination in Spain

Source Parameters of Weak Crustal Earthquakes of the Vrancea Region from Short-period Waveform Inversion

An Evaluation of the SCSN Moment Tensor Solutions: Robustness of the Mw Magnitude Scale, Style of Faulting, and Automation of the Method

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