How Fast Can We Reliably Estimate the Magnitude of Subduction Earthquakes?. Issue 18 (22nd September 2018)

• Record Type: Journal Article
• Authors: Leyton, F.; Ruiz, S.; Baez, J. C.; Meneses, G.; Madariaga, R.
• Is Part Of: Geophysical research letters. Volume 45:Issue 18(2018)
• Page Start: 9633
• Page End: 9641
• Publication Date: 2018-09-22
• Subjects: fast magnitude estimation -- earthquake early warning -- subduction earthquakes; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2018GL078991
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Fast and reliable characterization of earthquakes can provide vital information to the population, even reducing the effects of strong shaking produced by them. In this study, we explore the minimum time required to estimate the magnitude for subduction earthquakes. Using traditional P wave earthquake early warning parameters and considering a progressively increasing time window, we are able to estimate magnitude for subduction earthquakes ~30 s from the origin time (with an average residual of 0.01 ± 0.28). However, estimations for larger events (Mw ≥ 7.5) present larger errors (average residual of −0.70 ± 0.30). We complement our data with Global Navigational Satellite System observations for these events, enabling magnitude estimations ~70 s from the origin time (average residual of −0.42 ± 0.41). We propose that rapid estimations of magnitude should consider, initially, P waves in a progressively increasing time window, and complemented with GNSS data, for large events. Plain Language Summary: Fast and reliable magnitude estimation of earthquakes enables the preparation of the public to reduce its impact. Here we test known methods to rapidly estimate the magnitude of subduction earthquakes. We found encouraging results, taking a few tens of seconds to provide reliable values. However, results for larger events tend to underestimate the real magnitude. Hence, we propose the combination with other sources of information, such as Global Positioning System, that are able to resolve these larger events. Key Points: We calibrate coefficients from earthquake early warning methodologies to do a fast estimation of magnitude for subduction earthquakes These methodologies are able to robustly estimate the magnitude for small‐to‐moderate events (Mw ≤ 7.0) ~30 from origin time Large events (Mw ≥ 7.5) required data from GNSS to perform the magnitude estimation ~70 s from origin time