Fault-network geometry influences earthquake frictional behaviour

Area of Science:

• Geophysics
• Tectonics
• Earthquake Science

Background:

• Fault slip stability is a critical problem in fault mechanics.
• Fault geometry and roughness are known to influence slip behavior.
• Large-scale fault network complexities play a role in fault rupture.

Purpose of the Study:

• Investigate the link between fault-network geometry and surface creep rates.
• Propose a new perspective on fault creep mechanisms.
• Challenge traditional hypotheses on fault creep origins.

Main Methods:

• Analysis of fault-network geometry and surface creep rates in California, USA.
• Comparison of geometric complexity in creeping versus locked fault regions.

Main Results:

• Creeping fault groups exhibit simpler, less misaligned fault-network geometries.
• Locked fault regions display more complex fault-network geometries.
• Surface fault traces of creeping regions are simpler than those of locked regions.

Conclusions:

• Complex fault-network geometries cause geometric locking, promoting stick-slip behavior and earthquakes.
• Simpler fault geometries facilitate smooth fault creep.
• Fault friction alone does not fully explain earthquake behavior; geometry is also crucial.