INGV Finite Source

Seismic Sources and Fault Planes of the World’s Most Significant Earthquakes

The INGV Finite Source App provides seismic source models that illustrate the rupture distribution along the fault plane derived from the analysis of geodetic data. The sources are displayed on an interactive map and are accompanied by detailed technical and scientific information about each event. The catalog is continuously expanding with the inclusion of new and past events.

WHO THE APP IS FOR

The app is intended for anyone interested in exploring the characteristics of an earthquake and is particularly useful for understanding the spatial relationships between the seismic source and the surrounding territory. Seismologists and professionals in the field can access data, information and models that support both research and operational activities.

WHICH EARTHQUAKES ARE INCLUDED

The system manages global seismic events with magnitudes greater than 5.5. However, the catalog does not include all earthquakes above this threshold, but only those that have produced measurable permanent surface deformation, detectable through satellite imagery analysis (typically at least a few centimeters). These are, generally, earthquakes occurring on land or near coastlines and, depending on their magnitude, at relatively shallow depths.

HOW THE RUPTURE DISTRIBUTION IS DETERMINED

The finite source is computed using inversion algorithms applied to ground displacement data. In most cases, these data are obtained through Synthetic Aperture Radar Interferometry (InSAR), but solutions that integrate other techniques — such as Multi Aperture Interferometry (MAI), Pixel Offset Tracking (POT), and GPS — are also included. Seismological data are not currently used.

PUBLICATION TIME AFTER AN EARTHQUAKE

Depending on the availability of satellite data, the seismic source may be published within a few hours or several days after an event. For particularly complex earthquakes, involving multiple fault segments, publication may take longer. Although much of the analysis is automated, the rupture distribution on the fault plane is always reviewed, refined and validated by expert analysts prior to publication.

UPDATES AND REVISIONS

As new data or analyses become available, the rupture distribution on the fault plane may be updated at any time. Upon launching the app, users are notified of any updates to new or revised sources since their last use.

ACCESS TO DATA AND MODELS

Each earthquake source page provides a link to download data and models in ESRI Shapefile format, accompanied by a complete set of metadata.

SCENARIOS AND SATELLITE DATA INFORMATION

For major earthquakes, a scenario of the expected permanent displacements — based on focal mechanisms — is generated, along with information on satellite acquisition times and coverage. These details are useful for estimating the time required to compute the finite source. Scenarios and satellite coverage information, when available, are generated in near real-time following the event.

More information: https://finitesource.ingv.it/