Study on real-time correction of site amplification factor

Quancai Xie,Qiang Ma,Jingfa Zhang,Haiying Yu

doi:10.5194/nhess-19-2827-2019

Quancai Xie, Qiang Ma + Show 2 more

Open Access

https://doi.org/10.5194/nhess-19-2827-2019

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Abstract

Abstract. The site amplification factor was usually considered to be scalar values, such as amplification of peak ground acceleration or peak ground velocity, or increments of seismic intensity in the earthquake early warning (EEW) system or seismic-intensity repaid report system. This paper focuses on evaluating an infinite impulse recursive filter method that could produce frequency-dependent site amplification and compare the performance of the scalar-value method with the infinite impulse recursive filter method. A large number of strong motion data of IBRH10 and IBRH19 of the Kiban Kyoshin network (KiK-net) triggered in more than 1000 earthquakes from 2004 to 2012 were selected carefully and used to obtain the relative site amplification ratio; we model the relative site amplification factor with a casual filter. Then we make a simulation from the borehole to the surface and also simulate from the front-detection station to the far-field station. Compared to different simulation cases, it can easily be found that this method could produce different amplification factors for different earthquakes and could reflect the frequency-dependent nature of site amplification. Through these simulations between two stations, we can find that the frequency-dependent correction for site amplification shows better performance than the amplification factor relative to velocity (ARV) method and station correction method. It also shows better performance than the average level and the highest level of the Japan Meteorological Agency (JMA) earthquake early warning system in ground motion prediction. Some cases in which simulation did not work very well were also found; possible reasons and problems were analyzed and addressed. This method pays attention to the amplitude and ignores the phase characteristics; this problem may be improved by the seismic-interferometry method. Frequency-dependent correction for site amplification in the time domain highly improves the accuracy of predicting ground motion in real time.

Highlights

Real-time strong ground motion prediction has become an important part of earthquake early warning (EEW) systems
We focus on a full evaluation of the performance of this method by selecting a large number of Kiban Kyoshin network (KiK-net) data triggered in more than 1000 earthquakes; we a make simulation from the borehole to the surface and simulate from the front-detection station to the far-field station
The simulation from the borehole to the surface is not suitable for earthquake early warning systems, but it proves that this method shows good performance for simulating waveforms of the target station in real time

Summary

Introduction

Real-time strong ground motion prediction has become an important part of earthquake early warning (EEW) systems. There are many countries and regions that deploy operational earthquake early warning systems, like Mexico (Espinosa-Aranda et al, 1995, 2009), Japan (Kamigaichi, 2004; Hoshiba et al, 2008; Nakamura et al, 2009), Taiwan (Wu and Teng, 2002; Hsiao et al, 2009), Turkey (Erdik et al, 2003; Alcik et al, 2009), and Romania (Wenzel et al, 1999; Ionescu et al, 2007). The off-site warning utilizes a few seconds of seismogram observations at the first station and estimates the source parameters, such as the magnitude, epicenter distance, etc. Hoshiba et al (2008) mentioned that the Japan earthquake early warning system has been operational nationwide since October 2007 and is operated by the Japan Meteorological Agency (JMA).

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