Abstract
Determinations of surface-wave magnitude (Ms) are made on a consistent basis for 202 selected New Zealand earthquakes over the period 1901-1993, including most post-1942 events with local magnitude not less than 6.0 and centroid depth less than 45 km. These determinations have led to a reassessment of magnitudes and locations of some earlier events in the New Zealand Seismological Observatory Catalogue of local magnitudes (ML), in some cases with substantial revisions. The surface-wave magnitudes are compared with local magnitudes and moment magnitudes (Mw), where available, and the relations between these three variables and centroid depth are examined through regression models. The absence of surface-wave observations for some earthquakes allows an upper limit to be placed on their likely moment magnitudes. The analysis shows that estimates of Mw derived from Ms will have a standard error of about 0.15 and Mw derived from ML a standard error of about 0.3.
Highlights
This paper describes the estimation of the magnitudes of larger New Zealand earthquakes for the period 1901 to 1993
The above subjects were first addressed about six years ago [1,2] in an attempt to provide magnitudes estimated on a consistent basis for a set of 70 New Zealand earthquakes, based largely on surface-wave magnitudes
The need to extend the study to include more earthquakes, to include more Mw data, and to improve the inter-relationship modelling, has rapidly become pressing. This is partly due to the inadequacy of the New Zealand implementation of the M1, scale, but more fundamentally there is a need to model seismic hazard in the moment magnitude scale, because it has a clearer physical basis and is the scale most commonly used internationally in hazard modelling
Summary
Determinations of surface-wave magnitude (Ms) are made on a consistent basis for 202 selected New Zealand earthquakes over the period 1901-1993, including most post-1942 events with local magnitude not less than 6.0 and centroid depth less than 45 km. These determinations have led to a reassessment of magnitudes and locations of some earlier events in the New Zealand Seismological Observatory Catalogue of local magnitudes (ML), in some cases with substantial revisions. The surface-wave magnitudes are compared with local magnitudes and moment magnitudes (Mw), where available, and the relations between these three variables and centroid depth are examined through regression models. The analysis shows that estimates of Mw derived from Ms will have a standard error of about 0.15 and Mw derived from ML a standard error of about 0.3
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
