Estimating ground motions using recorded accelerograms

Heaton, Thomas H.; Tajima, Fumiko; Mori, A. W.

doi:10.1007/bf01904051

Cited by 147 publications

(62 citation statements)

References 27 publications

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“…Hence these data were converted to a common scale of moment magnitude (M w ). The local magnitudes were converted Heaton et al (1986), the body wave and surface wave magnitude were converted using the relations suggested by Scordilis (2006) and the intensity values were converted using the empirical relation (M=(2/3) I +1), where I is the earthquake intensity value. A declustering algorithm was used to remove the dependent events from this catalogue.…”

Section: Seismicity Characteristicsmentioning

confidence: 99%

Estimation of peak ground acceleration and spectral acceleration for South India with local site effects: probabilistic approach

Vipin

Anbazhagan

Sitharam

2009

Nat. Hazards Earth Syst. Sci.

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Abstract. In this work an attempt has been made to evaluate the seismic hazard of South India (8.0 • N-20 • N; 72 • E-88 • E) based on the probabilistic seismic hazard analysis (PSHA). The earthquake data obtained from different sources were declustered to remove the dependent events. A total of 598 earthquakes of moment magnitude 4 and above were obtained from the study area after declustering, and were considered for further hazard analysis. The seismotectonic map of the study area was prepared by considering the faults, lineaments and the shear zones in the study area which are associated with earthquakes of magnitude 4 and above. For assessing the seismic hazard, the study area was divided into small grids of size 0.1 • ×0.1 • , and the hazard parameters were calculated at the centre of each of these grid cells by considering all the seismic sources with in a radius of 300 km. Rock level peak horizontal acceleration (PHA) and spectral acceleration (SA) values at 1 s corresponding to 10% and 2% probability of exceedance in 50 years have been calculated for all the grid points. The contour maps showing the spatial variation of these values are presented here. Uniform hazard response spectrum (UHRS) at rock level for 5% damping and 10% and 2% probability of exceedance in 50 years were also developed for all the grid points. The peak ground acceleration (PGA) at surface level was calculated for the entire South India for four different site classes. These values can be used to find the PGA values at any site in South India based on site class at that location. Thus, this method can be viewed as a simplified method to evaluate the PGA values at any site in the study area.

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Section: Seismicity Characteristicsmentioning

confidence: 99%

Estimation of peak ground acceleration and spectral acceleration for South India with local site effects: probabilistic approach

Vipin

Anbazhagan

Sitharam

2009

Nat. Hazards Earth Syst. Sci.

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“…where l and w denote the length and width of the fault (Heaton et al, 1986). Below a depth of 6.0 km, the material properties on the fault surface are nearly uniform, so we use the shear modulus from a depth of 6.0 km in equation (14).…”

Section: Application To Strike-slip Faultmentioning

confidence: 99%

Dynamic Earthquake Ruptures in the Presence of Lithostatic Normal Stresses: Implications for Friction Models and Heat Production

Aagaard¹

2001

Bulletin of the Seismological Society of America

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We simulate dynamic ruptures on a strike-slip fault in homogeneous and layered half-spaces and on a thrust fault in a layered half-space. With traditional friction models, sliding friction exceeds 50% of the fault normal compressive stress, and unless the pore pressures approach the lithostatic stress, the rupture characteristics depend strongly on the depth, and sliding generates large amounts of heat. Under application of reasonable stress distributions with depth, variation of the effective coefficient of friction with the square root of the shear modulus and the inverse of the depth creates distributions of stress drop and fracture energy that produce realistic rupture behavior. This ad hoc friction model results in (1) low-sliding friction at all depths and (2) fracture energy that is relatively independent of depth. Additionally, friction models with rate-weakening behavior (which form pulselike ruptures) appear to generate heterogeneity in the distributions of final slip and shear stress more effectively than those without such behavior (which form cracklike ruptures). For surface rupture on a thrust fault, the simple slip-weakening friction model, which lacks rate-weakening behavior, accentuates the dynamic interactions between the seismic waves and the rupture and leads to excessively large ground motions on the hanging wall. Waveforms below the center of the fault (which are associated with waves radiated to teleseismic distances) indicate that source inversions of thrust events may slightly underestimate the slip at shallow depths.

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“…Regional moment tensor solutions still require complete broadband waveforms, and so require complete time series recovery before the inversion can commence. Though this means the M w cannot be computed as rapidly as with other magnitudes, an automated moment tensor solution can provide an improved estimate of magnitude that is less prone to saturation than magnitude scales based on limited frequency bandwidths (Kanamori, 1977;Heaton et al, 1986), though essentially the two scales should theoretically be equal (Deichmann, 2006). In addition, the moment tensor solution also documents the fault characteristics and constrains the depth, giving insight into the tectonic setting of the event.…”

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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Estimating ground motions using recorded accelerograms

Cited by 147 publications

References 27 publications

Estimation of peak ground acceleration and spectral acceleration for South India with local site effects: probabilistic approach

Estimation of peak ground acceleration and spectral acceleration for South India with local site effects: probabilistic approach

Dynamic Earthquake Ruptures in the Presence of Lithostatic Normal Stresses: Implications for Friction Models and Heat Production

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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