Full-waveform Inversion at the Mid-Ocean Ridge based on PI-LAB Experiment
Abstract
We perform full-waveform tomography for the Passive Imaging of the Lithosphere-Asthenosphere Boundary (PI-LAB) experiment to image the oceanic lithosphere and asthenosphere beneath 0 to 80 My seafloor. The experiment includes data from 39 broadband ocean bottom seismometers deployed at the equatorial mid-Atlantic ridge from 2016 to 2017. We use both high-frequency body waves down to 1 s period and long-period surface wave from local events. To accurately simulate wave propagation for the earthquakes we set up a spherical earth model covering 6 UTM zones with ocean-bottom topography and ocean layer consideration. The maximum depth of the model is set to 600 km. We use the local event moment tensor solutions determined from the PILAB array. We test several pre-existing models for instance PREM and a model determined by local body-wave tomography for the purpose of finding a good starting model for the simultaneous inversion. Results derived from the full-waveform tomography are compared with a joint inversion of the body and surface waves derived by ray methods for waveforms with periods > 30 s. We also examine the misfit kernels of the first iteration of these starting model to explore the effects of smoothing and damping constraints of these models and their effects on waveform mismatch. This investigation provides a basic comparison between wave-equation and ray-based tomography for the PI-LAB experiment, and the inversion for long-period waveforms provides a necessary step before moving to the short-period stage.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMS055.0009X
- Keywords:
-
- 7220 Oceanic crust;
- SEISMOLOGY;
- 7230 Seismicity and tectonics;
- SEISMOLOGY;
- 7245 Mid-ocean ridges;
- SEISMOLOGY;
- 7294 Seismic instruments and networks;
- SEISMOLOGY