Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Dineva, S. Articles by Mereu, R. Search for Related Content GeoRef GeoRef Citation

Energy Magnitude: A Case Study for Southern Ontario/Western Quebec (Canada)

The conventional methods for rapid determination of earthquake magnitude are based mainly on peak-to-peak amplitudes of specific phases on a seismic trace. Today, broadband digital records are readily accessible in real time, enabling the use of more information from a seismogram for rapid magnitude calculation.

The aim of this work is to introduce a new magnitude scale for routine seismological analysis, denoted M_E (P-wave, S-wave+coda, or both). This magnitude scale uses the signal energy and is illustrated here with a case study from southern Ontario/western Quebec (Canada). Traditional types of magnitude scales, based on the estimated maximum velocity (m_b) and Richter local magnitude (M_L), as well as the moment magnitude (M_W), and some other magnitude types, based on the coda energy (M_Coda) and envelope area (M_Env) are also computed for the study area for comparative purposes. The proposed approach employed for this study can be easily applied to any other region of the world.

The developed automatic procedure allowed the simultaneous computation of different magnitudes and different trace components and types of waves. The data used for this research are from 238 well-recorded earthquakes between 1991 and 2006 in southern Ontario/western Quebec/northern Ohio/northern NY State (1.0 < m_N < 5.5).

The results of our work show that, in general, magnitude values based on signal energy M_E give less scattered estimates than magnitude values based on peak-to-peak measurements. We recommend using M_E (S + coda) scale (vertical component) for quantifying the earthquakes in the study area in the future. The magnitude formula for this scale is given by M_E = 0.5log _S + 0.92logD + 3.56 + S, where _S is the signal energy defined here (Zv²_s t, v_S is measured in mm/s, t is the sample interval in seconds), D is the epicentral distance in km, and S is the station correction. The new M_E magnitude can be used for a quick estimate of the M_W magnitude for the study region using the relationship: M_W = M_E – 0.51 (for earthquakes with M_E 2.6), obtained here.