44 Relationships between magnitude scales

Utsu, Tokuji

doi:10.1016/s0074-6142(02)80247-9

Cited by 115 publications

(56 citation statements)

References 121 publications

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“…Here we determine the classic broad-band body wave magnitude (m B ) (Gutenberg, 1945) measured at periods of ~3.7 s (7.79) and ~7.3 s (7.83) after converting broadband P waves to Wiechert seismometer responses with dominant periods of 3.5 s and 10 s, respectively, for consistency with old events (Utsu, 2002;Bormann and Saul, 2009 that is ~0.35 magnitude units higher than the parallel trend found for typical interplate ruptures, and much higher than for tsunami earthquakes (Fig. 5a).…”

Section: Discussionmentioning

confidence: 99%

The 2017 M_w 8.2 Chiapas, Mexico, Earthquake: Energetic Slab Detachment

Lay

Bai

et al. 2017

Geophysical Research Letters

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On 8 September 2017, a great (Mw 8.2) normal faulting earthquake ruptured within the subducting Cocos Plate ~70 km landward from the Middle American Trench beneath the Tehuantepec gap. Iterative inversion and modeling of teleseismic and tsunami data and prediction of GPS displacements indicate that the steeply dipping rupture extended ~180 km to the northwest along strike toward the Oaxaca coast and from ~30 to 70 km in depth, with peak slip of ~13 m. The rupture likely broke through the entire lithosphere of the young subducted slab in response to downdip slab pull. The plate boundary region between the trench and the fault intersection with the megathrust appears to be frictionally coupled, influencing location of the detachment. Comparisons of the broadband body wave magnitude (mB) and moment‐scaled radiated energy (ER/M0) establish that intraslab earthquakes tend to be more energetic than interplate events, accounting for strong ground shaking observed for the 2017 event.

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Section: Discussionmentioning

confidence: 99%

The 2017 M_w 8.2 Chiapas, Mexico, Earthquake: Energetic Slab Detachment

Lay

Bai

et al. 2017

Geophysical Research Letters

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“…M D is adopted as M J only when M D is able to be estimated. It is well known that M J is almost the same as M w up to around 8 on the average (Utsu, 1982;Katsumata, 2004). However, when a magnitude is more than 8, M J is not appropriate due to the saturation of amplitude-magnitude.…”

Section: Methods For Estimating Parametersmentioning

confidence: 89%

Outline of the 2011 off the Pacific coast of Tohoku Earthquake (M w 9.0) —Seismicity: foreshocks, mainshock, aftershocks, and induced activity—

Hirose¹,

Miyaoka

Hayashimoto³

et al. 2011

Earth Planet Sp

168

102

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A massive earthquake of a magnitude (M) of 9.0 occurred on March 11, 2011, off the Pacific coast of the northeastern part of Honshu, Japan. Centroid Moment Tensor analysis of the mainshock indicates that it was the reverse fault type, with a WNW-ESE compressional axis. The earthquake occurred on the plate boundary between the island arc and the Pacific plates. Three aftershocks exceeding M 7 occurred within 40-min after the mainshock, and the aftershock area covered a wide range of 500-km × 200-km. Seismicity became active one month before the mainshock, and it continued for two weeks in an adjacent area northeast of the mainshock. Furthermore, foreshock activity with maximum M 7.3 started in the same area two days before the mainshock. Seismic activities increased in almost the entire area of the Japanese Islands after the mainshock. We infer that these earthquakes were induced by the mainshock. JMA displacement-amplitude magnitude of the mainshock was determined to be 8.4, which was smaller than the moment magnitude of 9.0. Key words: Foreshock and aftershock, massive earthquake on the plate boundary, induced seismicity, northeastern Japan.

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“…As previously specified, estimated moment magnitude values were considered for historical data, whereas local magnitudes M L were used for instrumental events. The merging of these two kinds of magnitude is justified by the observation that at magnitude lower than 4.5 the M L values are comparable with the M W ones within the few tenths of unit uncertainty commonly affecting magnitude estimates (see Utsu, 2002). Figure 6 shows an example of the event number distribution with magnitude.…”

Section: Estimates Of Seismicity Ratesmentioning

confidence: 94%

Seismogenic zonation and seismic hazard estimates in a Southern Italy area (Northern Apulia) characterised by moderate seismicity rates

Gaudio

Pierri

Calcagnile

2009

Nat. Hazards Earth Syst. Sci.

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Abstract. The northernmost part of Apulia, in Southern Italy, is an emerged portion of the Adriatic plate, which in past centuries was hit by at least three disastrous earthquakes and at present is occasionally affected by seismic events of moderate energy. In the latest seismic hazard assessment carried out in Italy at national scale, the adopted seismogenic zonation (named ZS9) has defined for this area a single zone including parts of different structural units (chain, foredeep, foreland). However significant seismic behaviour differences were revealed among them by our recent studies and, therefore, we re-evaluated local seismic hazard by adopting a zonation, named ZNA, modifying the ZS9 to separate areas of Northern Apulia belonging to different structural domains. To overcome the problem of the limited datasets of historical events available for small zones having a relatively low rate of earthquake recurrence, an approach was adopted that integrates historical and instrumental event data. The latter were declustered with a procedure specifically devised to process datasets of low to moderate magnitude shocks. Seismicity rates were then calculated following alternative procedural choices, according to a "logic tree" approach, to explore the influence of epistemic uncertainties on the final results and to evaluate, among these, the importance of the uncertainty in seismogenic zonation. The comparison between the results obtained using zonations ZNA and ZS9 confirms the well known "spreading effect" that the use of larger seismogenic zones has on hazard estimates. This effect can locally determine underestimates or overestimates by amounts that make necessary a careful reconsideration of seismic classification and building code application.

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44 Relationships between magnitude scales

Cited by 115 publications

References 121 publications

The 2017 M_w 8.2 Chiapas, Mexico, Earthquake: Energetic Slab Detachment

The 2017 M_w 8.2 Chiapas, Mexico, Earthquake: Energetic Slab Detachment

Outline of the 2011 off the Pacific coast of Tohoku Earthquake (M w 9.0) —Seismicity: foreshocks, mainshock, aftershocks, and induced activity—

Seismogenic zonation and seismic hazard estimates in a Southern Italy area (Northern Apulia) characterised by moderate seismicity rates

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44 Relationships between magnitude scales

Cited by 115 publications

References 121 publications

The 2017 Mw 8.2 Chiapas, Mexico, Earthquake: Energetic Slab Detachment

The 2017 Mw 8.2 Chiapas, Mexico, Earthquake: Energetic Slab Detachment

Outline of the 2011 off the Pacific coast of Tohoku Earthquake (M w 9.0) —Seismicity: foreshocks, mainshock, aftershocks, and induced activity—

Seismogenic zonation and seismic hazard estimates in a Southern Italy area (Northern Apulia) characterised by moderate seismicity rates

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Resources

About

The 2017 M_w 8.2 Chiapas, Mexico, Earthquake: Energetic Slab Detachment

The 2017 M_w 8.2 Chiapas, Mexico, Earthquake: Energetic Slab Detachment