A decade of short-period earthquake rupture histories from multi-array back-projection

Cite as:

Vera, Felipe; Tilmann, Frederik; Saul, Joachim (2024): A decade of short-period earthquake rupture histories from multi-array back-projection. V. 3.0. GFZ Data Services. https://doi.org/10.5880/GFZ.2.4.2024.001

Status

I N R E V I E W : Vera, Felipe; Tilmann, Frederik; Saul, Joachim (2024): A decade of short-period earthquake rupture histories from multi-array back-projection. V. 3.0. GFZ Data Services. https://doi.org/10.5880/GFZ.2.4.2024.001

Abstract

Teleseismic back-projection imaging has emerged as a powerful tool for understanding the rupture propagation of large earthquakes. However, its application often suffers from artifacts related to the receiver array geometry.

We developed a teleseismic back-projection technique that can accommodate data from multiple arrays. Combined processing of P and pP waveforms may further improve the resolution. The method is suitable for defining arrays ad-hoc to achieve a good azimuthal distribution for most earthquakes. We present a catalog of short-period rupture histories (0.5-2.0 Hz) for all earthquakes from 2010 to 2022 with Mw {greater than or equal to} 7.5 and depth less than 200 km (56 events). The method provides automatic estimates of rupture length, directivity, speed, and aspect ratio, a proxy for rupture complexity.

We obtained short-period rupture length scaling relations that are in good agreement with previously published relations based on estimates of total slip. Rupture speeds were consistently in the sub-Rayleigh regime for thrust and normal earthquakes, whereas a tenth of strike-slip events propagated at supershear speeds. Many rupture histories exhibited complex behaviors, e.g., rupture on conjugate faults, bilateral propagation, and dynamic triggering by a P wave. For megathrust earthquakes, ruptures encircling asperities were frequently observed, with down-dip, up-dip, and balanced patterns. Although there is a preference for short-period emissions to emanate from central and down-dip parts of the megathrust, emissions up-dip of the main asperity are more frequent than suggested by earlier results.

The data are presented as follows (and described in detail in the associated README):

SUPPORTING DATA SET S1 (2024-001_Vera-et-al_Supporting-Data-S1.zip)

This Data Set (S1) consists of *.bp files containing (1) short-period earthquake rupture patterns, (2) energy radiated maps, and (3) source time functions derived from back-projections (0.5-2.0 Hz). The Data Set S1 includes 56 folders, representing 56 processed earthquakes between 2010 and 2022 with a moment magnitude (Mw) greater than or equal to 7.5 and a depth less than 200 km. These folders are labeled in the format YYYYMMDDhhmm_EVENT_NAME_REGION (UTC) in *.bp format.

SUPPORTING DATA SET S2 (2024-001_Vera-et-al_Supporting-Data-S2.csv)

This Data Set (S2) comprises a *.csv file containing earthquake source information used in the back-projection and the resulting rupture parameter estimates based on **visually determined** rupture end times. The *.csv file includes rupture parameter estimates for each of the 56 earthquake back-projections presented in Data Set S1.

SUPPORTING DATA SET S3 (2024-001_Vera-et-al_Supporting-Data-S3.csv)

This Data Set (S3) comprises a *.csv file containing earthquake source information used in the back-projection and the resulting rupture parameter estimates based on **automatic** rupture end times. Note: The main difference from Data Set S2 is that rupture parameter estimates in S3 are derived from **automated** rupture end times, whereas S2 provided estimates relative to **visually determined** rupture end times.

Authors

Vera, Felipe;GFZ German Research Centre for Geosciences, Potsdam, Germany
Tilmann, Frederik;GFZ German Research Centre for Geosciences, Potsdam, Germany
Saul, Joachim;GFZ German Research Centre for Geosciences, Potsdam, Germany

Contact

Vera, Felipe; GFZ German Research Centre for Geosciences, Potsdam, Germany;
Tilmann, Frederik; GFZ German Research Centre for Geosciences, Potsdam, Germany;