Source Scaling of Inland Crustal Earthquake Sequences in Japan Using the S-Wave Coda Spectral Ratio Method

Somei, Kazuhiro; Asano, Kimiyuki; Iwata, Tomotaka; Miyakoshi, Ken

doi:10.1007/s00024-014-0774-2

Cited by 23 publications

(14 citation statements)

References 58 publications

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“…Since there is a trade-off between the f ci included in S i f and t * ij (e.g., Scherbaum 1990; Ko et al 2012), before evaluating t * ij , we independently estimate f ci using a procedure exploited by Somei et al (2014), which is based on the S-wave coda spectral ratio method (e.g., Aki and Chouet 1975) (see Additional file 1: Section 1 and Figure S1 for the description and example of the f c estimation).…”

Section: Is Rewritten Asmentioning

confidence: 99%

Three-dimensional P- and S-wave attenuation structures around the source region of the 2016 Kumamoto earthquakes

Komatsu

Takenaka

Oda

2017

Earth Planets Space

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We investigate the three-dimensional P-and S-wave attenuation (Q −1 P and Q −1 S ) structures of the crust around the source region of the 2016 Kumamoto earthquakes, Japan. To estimate the attenuation structures, the path-averaged attenuation factor t * is estimated from the amplitude decay rate of the P-and S-wave spectra corrected for the source spectrum. The Q −1 P and Q −1 S structures are estimated by tomography using t * for the P-and S-waves, respectively. Several features are found in the attenuation structures as follows: In the source region, two high-Q P and high-Q S zones exist along the Futagawa and the Hinagu fault segments in the upper crust. The high-Q P and high-Q S zone along the Futagawa fault segment is found to include the large-slip area of the mainshock obtained from a source inversion study. In the lower crust, the low Q P is distributed beneath the entire source region. A low-Q P and low-Q S zone also exists beneath the Kuju and Aso volcanoes, which is consistent with the shallow limited depth extent of the seismogenic zone due to high temperature. The western edge of this zone adjoins the eastern edge of the high-Q P and high-Q S area, including the large-slip area.

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Section: Is Rewritten Asmentioning

confidence: 99%

Three-dimensional P- and S-wave attenuation structures around the source region of the 2016 Kumamoto earthquakes

Komatsu

Takenaka

Oda

2017

Earth Planets Space

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“…Figure shows M 0 and f c values estimated from the D‐cluster and F‐cluster events, along with results from previous studies for comparison [ Urbancic and Young , ; Abercrombie , ; Urbancic et al , ; Collins and Young , ; Hiramatsu et al , ; Ide et al , ; Prieto et al , ; Abercrombie and Rice , ; Oye et al , ; Yamada et al , ; Domanski and Gibowicz , ; Kwiatek et al , ; Kwiatek et al , ; Kwiatek et al , ; Somei et al , ]. In Figures b and c, M 0 and f c values are estimated for the D‐cluster and F‐cluster events together with error bars.…”

Section: Source Parametersmentioning

confidence: 99%

Magnitude −7 level earthquakes: A new lower limit of self‐similarity in seismic scaling relationships

Yoshimitsu

Kawakata

Takahashi

2014

Geophysical Research Letters

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Microfractures occurring in a rock sample that are called acoustic emission (AE) events show some similar features to earthquakes. However, it remains to be shown whether or not AE equate to ultramicroearthquakes. In this study, we show the existence of magnitude À7 level earthquakes based on seismological analyses of AE source parameters. Advances in multichannel, broadband, high-speed continuous recording of AE under seismogenic pressure conditions has facilitated increasingly robust measurement. Source parameters of AE show that AE events satisfy the same scaling relationship as natural earthquakes in which seismic moment is inversely proportional to the cube of corner frequency. This result suggests that both millimeter scale fractures and natural earthquakes of kilometer scale ruptures are highly similar as physical processes. Hence, AE events can be interpreted as ultramicroearthquakes having a magnitude of about À7. These results demonstrate that laboratory observation is an effective approach in studying natural earthquake generation process.

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“…We require envelope SNR of a minimum of 2; envelopes for event pairs that met this criteria were used to determine source ratios for each band. Source parameter results based on data from coda are similar to those based on direct wave data, with reduced scatter in the spectral ratios [e.g., Mayeda et al, 2007;Mayeda and Malagnini, 2010;Abercrombie, 2013;Fisk and Phillips, 2013;Yoo and Mayeda, 2013;Somei et al, 2014]. Median event separations for each cluster (horizontal and depth separation of 17 km and 10 km (c1), 10 km and 8 km (c2), and 11 km and 6 km (c3), respectively) are within commonly used ranges for previous spectral ratio studies [e.g., Malagnini and Mayeda, 2008;Mayeda and Malagnini, 2010;Baltay et al, 2010] Stress drop (Δσ) using Madariaga [1976], corner frequency (f c ), and seismic moment (M o ) are determined from the source spectral ratios of the envelopes, which are dominated by the S-coda.…”

Section: Spectral Ratio Methodsmentioning

confidence: 78%

Low stress drop earthquakes in the rupture zone of the 1992 Nicaragua tsunami earthquake

Bilek

Rotman

Phillips

2016

Geophysical Research Letters

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Tsunami earthquakes, events that generate larger than expected tsunami and are deficient in high‐frequency seismic radiation, are rare but hazardous to coastal populations. One model for these events is shallow rupture through low‐strength materials. We calculate seismic moment, corner frequency, and stress drop for 216 earthquakes (2.1 < Mw < 4.7, November 2005 to June 2006) within and external to the 1992 Nicaragua tsunami earthquake rupture zone to test the hypothesis that differences in fault zone properties defined the limits of the 1992 tsunami rupture zone and continue to produce spatial variations in earthquake source properties. Mean stress drop of events within the rupture area is 1.2 MPa, and 5.5 MPa for events just outside of the rupture zone, with similar magnitude earthquakes in each group. Our results demonstrate different source parameter characteristics for microseismicity in the region of a past tsunami earthquake.

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Source Scaling of Inland Crustal Earthquake Sequences in Japan Using the S-Wave Coda Spectral Ratio Method

Cited by 23 publications

References 58 publications

Three-dimensional P- and S-wave attenuation structures around the source region of the 2016 Kumamoto earthquakes

Three-dimensional P- and S-wave attenuation structures around the source region of the 2016 Kumamoto earthquakes

Magnitude −7 level earthquakes: A new lower limit of self‐similarity in seismic scaling relationships

Low stress drop earthquakes in the rupture zone of the 1992 Nicaragua tsunami earthquake

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