Geodetic Observations of Weak Determinism in Rupture Evolution of Large Earthquakes

Area of Science:

• Seismology
• Geophysics
• Earthquake Science

Background:

• Determining the exact moment large earthquakes become dissimilar from smaller ones is key for effective early warning.
• Traditional seismic methods struggle to rapidly estimate magnitudes of large earthquakes, especially near the source.
• Global Navigation Satellite System (GNSS) data offers real-time magnitude estimation capabilities, even for the largest events.

Purpose of the Study:

• To investigate early rupture metrics using combined seismic and geodetic data.
• To determine if observational data supports deterministic earthquake rupture behavior.
• To assess the feasibility of predicting final earthquake magnitude from early rupture characteristics.

Main Methods:

• Integration of seismic data with Global Navigation Satellite System (GNSS) geodetic data.
• Analysis of early rupture metrics within the initial seconds of seismic events.
• Comparison of early-stage earthquake behavior with final rupture extent.

Main Results:

• The earliest seismic metrics (around 5 seconds) are insufficient for predicting final earthquake magnitude.
• Accurate earthquake magnitude estimates are achievable within tens of seconds, before rupture completion.
• Findings suggest a weak form of earthquake determinism, where early data provides predictive power.

Conclusions:

• Early rupture metrics, particularly when combined with GNSS data, offer valuable insights into earthquake magnitude prediction.
• The study supports a weak determinism in earthquake rupture processes.
• Results have significant implications for improving earthquake and tsunami early warning systems through enhanced magnitude estimation.