Earthquake forecasting during the complex Amatrice-Norcia seismic sequence.

Area of Science:

• Seismology
• Earthquake Science
• Geophysics

Background:

• Earthquake forecasting is crucial for risk mitigation but challenging.
• Reliable short-term forecasts are typically limited to simple aftershock sequences following Omori's law.
• Complex seismic sequences often deviate from these predictable patterns.

Purpose of the Study:

• To evaluate the Italian operational earthquake forecasting system's performance.
• To assess the system's ability to forecast large earthquakes during complex seismic sequences.
• To determine if reliable forecasts are possible beyond typical aftershock scenarios.

Main Methods:

• Utilized the current Italian operational earthquake forecasting system.
• Analyzed the 2016-2017 Amatrice-Norcia seismic sequence, known for its complexity.
• Assessed space-time-magnitude forecast skill and statistical reliability.

Main Results:

• The system provided statistically reliable and skillful forecasts for major earthquakes during the Amatrice-Norcia sequence.
• The sequence exhibited multiple seismicity bursts and significant deviations from the Omori law.
• Forecasts proved effective despite the complex and atypical nature of the seismic activity.

Conclusions:

• Operational earthquake forecasting systems can achieve reliable and skillful predictions even in complex seismic sequences.
• This capability is vital for supporting public decision-makers and citizens in managing seismic risks.
• The findings advance the potential for effective earthquake risk management during unusual seismic events.