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Early magnitude estimation for the MW7.9 Wenchuan earthquake using progressively expanded P-wave time window.

Peng C, Yang J, Zheng Y, Xu Z, Jiang X - Sci Rep (2014)

Bottom Line: This information would have been available 40 s after the earthquake origin time and could have been refined in the successive 20 s using data from more distant stations.The reason for the magnitude underestimation is in part a combined effect of high-pass filtering and frequency dependence of the main radiating source during the rupture process.Finally we suggest only using Pd alone for magnitude estimation because of its slight magnitude saturation compared to the τc magnitude.

View Article: PubMed Central - PubMed

Affiliation: Institute of Geophysics, China Earthquake Administration, No. 5 Minzudaxue South Road, Haidian District, Beijing 100081, China.

ABSTRACT
More and more earthquake early warning systems (EEWS) are developed or currently being tested in many active seismic regions of the world. A well-known problem with real-time procedures is the parameter saturation, which may lead to magnitude underestimation for large earthquakes. In this paper, the method used to the MW9.0 Tohoku-Oki earthquake is explored with strong-motion records of the MW7.9, 2008 Wenchuan earthquake. We measure two early warning parameters by progressively expanding the P-wave time window (PTW) and distance range, to provide early magnitude estimates and a rapid prediction of the potential damage area. This information would have been available 40 s after the earthquake origin time and could have been refined in the successive 20 s using data from more distant stations. We show the suitability of the existing regression relationships between early warning parameters and magnitude, provided that an appropriate PTW is used for parameter estimation. The reason for the magnitude underestimation is in part a combined effect of high-pass filtering and frequency dependence of the main radiating source during the rupture process. Finally we suggest only using Pd alone for magnitude estimation because of its slight magnitude saturation compared to the τc magnitude.

No MeSH data available.


Related in: MedlinePlus

Distribution of stations (triangles) used in this study with the closest station 51WCW shown as a larger size triangle.The black star represents the epicentre of the 2008 MW 7.9 Wenchuan earthquake. The thin lines are faults described in Deng et al.38. The star on the inset marks the study region in China. This figure is drawn using GMT software49.
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f1: Distribution of stations (triangles) used in this study with the closest station 51WCW shown as a larger size triangle.The black star represents the epicentre of the 2008 MW 7.9 Wenchuan earthquake. The thin lines are faults described in Deng et al.38. The star on the inset marks the study region in China. This figure is drawn using GMT software49.

Mentions: We analyzed 60, 3-component strong-motion accelerometer records for the Wenchuan earthquake, in the distance range between 0 and 200 km from the rupture. Waveforms were extracted from the CSMNC database. The sampling rates are 200 samples per second. Figure 1 shows the distribution of selected stations. We measured the initial peak displacement, Pd, and the predominant period, τc, after single and double integration to get velocity and displacement, respectively.


Early magnitude estimation for the MW7.9 Wenchuan earthquake using progressively expanded P-wave time window.

Peng C, Yang J, Zheng Y, Xu Z, Jiang X - Sci Rep (2014)

Distribution of stations (triangles) used in this study with the closest station 51WCW shown as a larger size triangle.The black star represents the epicentre of the 2008 MW 7.9 Wenchuan earthquake. The thin lines are faults described in Deng et al.38. The star on the inset marks the study region in China. This figure is drawn using GMT software49.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4209451&req=5

f1: Distribution of stations (triangles) used in this study with the closest station 51WCW shown as a larger size triangle.The black star represents the epicentre of the 2008 MW 7.9 Wenchuan earthquake. The thin lines are faults described in Deng et al.38. The star on the inset marks the study region in China. This figure is drawn using GMT software49.
Mentions: We analyzed 60, 3-component strong-motion accelerometer records for the Wenchuan earthquake, in the distance range between 0 and 200 km from the rupture. Waveforms were extracted from the CSMNC database. The sampling rates are 200 samples per second. Figure 1 shows the distribution of selected stations. We measured the initial peak displacement, Pd, and the predominant period, τc, after single and double integration to get velocity and displacement, respectively.

Bottom Line: This information would have been available 40 s after the earthquake origin time and could have been refined in the successive 20 s using data from more distant stations.The reason for the magnitude underestimation is in part a combined effect of high-pass filtering and frequency dependence of the main radiating source during the rupture process.Finally we suggest only using Pd alone for magnitude estimation because of its slight magnitude saturation compared to the τc magnitude.

View Article: PubMed Central - PubMed

Affiliation: Institute of Geophysics, China Earthquake Administration, No. 5 Minzudaxue South Road, Haidian District, Beijing 100081, China.

ABSTRACT
More and more earthquake early warning systems (EEWS) are developed or currently being tested in many active seismic regions of the world. A well-known problem with real-time procedures is the parameter saturation, which may lead to magnitude underestimation for large earthquakes. In this paper, the method used to the MW9.0 Tohoku-Oki earthquake is explored with strong-motion records of the MW7.9, 2008 Wenchuan earthquake. We measure two early warning parameters by progressively expanding the P-wave time window (PTW) and distance range, to provide early magnitude estimates and a rapid prediction of the potential damage area. This information would have been available 40 s after the earthquake origin time and could have been refined in the successive 20 s using data from more distant stations. We show the suitability of the existing regression relationships between early warning parameters and magnitude, provided that an appropriate PTW is used for parameter estimation. The reason for the magnitude underestimation is in part a combined effect of high-pass filtering and frequency dependence of the main radiating source during the rupture process. Finally we suggest only using Pd alone for magnitude estimation because of its slight magnitude saturation compared to the τc magnitude.

No MeSH data available.


Related in: MedlinePlus