Empirical Relationships based on the P-wave Envelop for Distance and Magnitude Estimation for Earthquake Early Warning in Iran

Document Type : Seismology and Engineering Seismology


1 Road, Housing and Urban Development Research Center

2 Road, Housing & Urban Development Research Center


The main goal of an Earthquake Early Warning (EEW) system is to reduce the damaging effects of the hazardous earthquakes. The characterization of an earthquake for EEW includes most importantly, the estimates of its size (magnitude) and location. In this study, the distance and magnitude of the selected earthquakes were estimated using the envelope of the initial part of the P-waveforms deploying a single seismic record. The method so called "B-delta" [1] is used to find the EEW parameters. In total, 1210 records (vertical component) with 4.0 £M 7.7 and epicentral distance up to 300 km is used. The root mean square error (RMSE) of epicentral distance estimations using 2 and 3 sec P-wave time windows are 0.260 and 0.261 on a logarithmic scale respectively. Additionally, the C-D method [2] was performed to check if this method provides more accurate estimates. Results show no significant differences between the final estimates of the two methods. Furthermore, using the obtained epicentral distance, the magnitude was estimated by employing empirical magnitude-amplitude relationships. The magnitude RMSE of both methods is in range of 0.6-0.7. Results suggest that the final magnitude of the large events would be underestimated using just few seconds of P-wave; however, the magnitude estimates can be used as the minimum threshold for the final size of the ongoing event. Moreover, short term average/long term average method was used for automatic P-wave arrival detection. The result shows 76% success in P-wave arrival detection. This method can be utilized in real time EEW practices.


Odaka, T., Ashiya, K., Tsukada, S., Sato, S., Ohtake, K., and Nozaka, D. (2003) A new method of quickly estimating epicentral distance and magnitude from a single station record. Bull. Seismol. Soc. Am., 93(1), 526–532.
Iwata, N., Yamamoto, S., Korenaga, M., and Noda, S. (2015) Improved algorithms of seismic parameter estimations and noise discrimination in earthquake early warning. Quarterly Report of RTRI, 56(4), 291-298.
Allen, R.M. and Kanamori, H. (2003) The potential for earthquake early warning in southern California. Science, 300(5620), 786–789.
Wu, Y.M., and Kanamori, H. (2005) Experiment on an onsite early warning method for the Taiwan early warning system. Bull. Seismol. Soc. Am., 95(1), 347- 353.
Allen, R.M., Gasparini, P., Kamigaichi, O., and Böse, M. (2009) The status of earthquake early warning around the world: An introductory overview. Seismological Research Letters, 81(5), 682-693.
Noda, S., Yamamoto, S., and Sato, S. (2012b) New Method for Estimating Earthquake Parameters for Earthquake Early Warning. Quarterly Report of RTRI, 53(2), 112-116.
Bito, Y. and Nakamura, Y. (1986) Urgent earthquake detection and alarm system. Civil Engineering in Japan, Japan Society of Civil Engineers, Tokyo, Japan, 103–116.
Nakamura, Y. (1988) On the urgent earthquake detection and alarm system (UrEDAS). Proc. of Ninth World Conference on Earthquake Engineering, Tokyo, Japan, (VII), 673–678.
Odaka, T., Nakamura, H., and Ashiya, K. (2005) Difference in the initial slopes of the P-wave envelope waveforms of the main shock M7.4 and foreshock M7.1 of the 2004 off the Kii peninsula earthquakes. Earth, Planets and Space, 57(4), 333-337.
Noda, S., Yamamoto, S., Sato, S., Iwata, N., Korenaga, M., and Ashiya, K. (2012a) Improvement of back-azimuth estimation in real-time by using a single station record. Earth, planets and space, 64(3), 315-318.
Yamamoto, S. and Tomori, M. (2013) Earthquake Early Warning system for railways and its performance, Journal of JSCE, 1, 322-328.
Yamamoto, S., Iwata, N., Noda, S., and Korenaga, M. (2015) Improvement of the single-station EEW algorithms for railways. Japan Geoscience Union Meeting.
Kamigaichi, O., Saito, M., Doi, K., Matsumori, T., Tsukada, S., Takeda, K., Himoyama, T., Nakamura, K., Kiyomoto, M., and Watanabe, Y. (2009) Earthquake early warning in Japan: warning the general public and future prospects. Seismol. Res. Lett., 80, 717–726.
Doi, K. (2011) The operation and performance of earthquake early warnings by the Japan Meteorological Agency. Soil Dynam. Earthq. Eng., 31,119-126, doi: 10.1016/j.soildyn.2010.06.009.
Horiuchi, S., Negishi, H., Abe, K., Kamimura, A., and Fujiwara, Y. (2005) An automatic processing system for broadcasting earthquake alarms. Bull. Seismol. Soc. Am., 95(2), 708–718.
Heidari, H. (2016) Quick estimation of the magnitude and epicentral distance using the P wave for earthquakes in Iran. Bull. Seismol. Soc. Am., 106(1), 225-231, doi: 10.1785/0120150090.
Mahood, M., Mokhtari, M., and Zafarani, H. (2016) Prediction of magnitude and epicentral distance from a single seismic record: A case study of the Ahar-Varzaghan earthquake. International Journal of Geohazards and Environment, 2(4): 208-213.
Allen, R.V. (1978) Automatic earthquake recognition and timing from single traces. Bull. Seismol. Soc. Am., 68(5), 1521-1532.
Railway Technical Research Institute (RTRI) (2016) Annual report 2012-2013, P. 11. (http://www.rtri.or.jp/ last accessed 2016).
Hoshiba, Y., Iwakiri, K., Hayashimoto, N., Shimoyama, T., Hirano, K., Yamada, Y., Ishigaki, Y., and Kikuta, H. (2011) Outline of the 2011 off the Pacific coast of Tohoku Earthquake (M 9.0) Earthquake Early Warning and observed seismic intensity. Earth, Planets and Space, 63, 547–551.
Yamamoto, S., Sato, S., Iwata, N., Korenaga, M., Ito, Y., and Noda, S. (2011) Improvement of seismic parameter estimation for the Earthquake Early Warning System. Quart. Rep. RTRI, 52(4), 206–209, CrossRef (http://dx.doi.org/10.2219/rtriqr.52.206).
Japan Meteorological Agency (2011) Retrieved from http://www.seisvol.kishou.go.jp/eq/EEW/kaisetsu/joho/20110311144640/content/content_out.html, last accessed July, 2013.