datasets

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pdf-italy

Probability Map of Distributed Faulting in Italy

PDF-Italy 1.0 is a national-scale conditional probabilistic map of distributed faulting. This work builds upon and extends a previous DPC-funded initiative on DISS–ITHACA interoperability (published on: https://diss.ingv.it/ithdiss/), enhancing the joint use of the two datasets within a unified hazard framework. PDF-Italy includes two products: 1) a continuous map of distributed faulting likelihood across Italy, produced by aggregating conditional probabilities over a regular grid, and 2) an application to the ITHACA faults, providing probability estimates directly on the mapped structures.
Surface faulting induced by moderate-to-large earthquakes (Mw ≥5.5) may represent a significant hazard for infrastructures, as coseismic slip may propagate to the surface and activate both primary and secondary structures, producing distributed faulting, consisting of secondary ruptures and deformation affecting wide areas around the main fault.
The maps provided by PDF-Italy offer a quantitative representation of the spatial distribution of distributed faulting probabilities across Italy and on the mapped ITHACA faults. The probabilities shown are conditional probabilities, expressing the likelihood of distributed faulting associated with a moderate-to-large earthquake (Mw ≥ 5.5) occurring on a given source fault. They do not represent the probability that distributed faulting will occur within a specified time interval. Because distributed faulting can only occur if the causative earthquake takes place, the actual absolute probability of observing such phenomena at a given location and within a given period of time is substantially lower than the conditional probabilities displayed in the maps. Probabilities in Panel A of the figure are computed only for locations within 25 km of mapped seismogenic sources; areas farther away are assigned a probability of zero. The color scale in the maps is intended to highlight relative spatial variations in distributed faulting likelihood within earthquake scenarios and should not be interpreted as a measure of time-dependent hazard. Future developments will integrate fault slip rates and earthquake recurrence information to derive time-dependent probabilities.

Figure. PDF-Italy products. (A) National-scale map of distributed faulting conditional probabilities associated with moderate-to-large earthquakes (Mw ≥ 5.5), calculated on a regular grid. (B) Conditional probabilities projected onto the mapped fault traces of the ITHACA database. Colors indicate relative variations in conditional probability within the modeled earthquake scenarios and should not be interpreted as time-dependent probabilities of occurrence.

Details: Category: datasets

sfit

Database of Surface Faulting events in ITaly - SFIT

seismic rupture Norcia 2016 - Vettoretto — Principal coseismic rupture traces produced by the 2016 Norcia running along the flank of Mt. Vettoretto.
These rupture lines could be followed for a total extent of about 22 km. Credit: INGV.

The database of Surface Faulting events of Italy (SFIT) is a comprehensive compilation of published data on earthquake surface fault ruptures in Italy over the last century. The first release of the database documents six major events: the 1915 Avezzano (M7.0), 1980 Irpinia (M6.9), 1997 Umbria-Marche (M6.0), 2009 L’Aquila (M6.3), 2016 Norcia (M6.6), and 2018 Etna-Fleri (M5.0) earthquakes.

SFIT integrates, organizes, and harmonizes heterogeneous datasets derived from previously published compilations and scientific literature into a unified structure. All data included in the database are derived from previously published data sources. The database spans different tectonic environments and includes earthquakes with different magnitudes, rupture styles, and geological contexts.

Over the past decades, both the quantity and the resolution of available observations have increased significantly. While historical earthquakes inevitably carry greater spatial uncertainty, SFIT applies modern standards of data organization, image documentation, and georeferencing to ensure that these records remain scientifically robust and comparable through time.

SFIT contains a wide range of information on points and traces of surface rupture collected in the field. The primary value of SFIT lies in its ability to centralize several data types within a single, searchable, open-access database. In addition, SFIT provides for the first time a collection of images, primarily photographic documentation, georeferenced and associated with the surface ruptures, representing a precious visual record of the observed deformation. The significance of mapped surface ruptures is classified following the original interpretation in the data source through a ranking code that systematically distinguishes principal ruptures from distributed, triggered, or ground-shaking-induced ruptures.

Principal coseismic surface ruptures represent the direct geomorphic expression of slip occurring along a fault during an earthquake (i.e. surface faulting). Their spatial distribution, geometry, kinematics and size provide a critical proxy for understanding the location, geometry, and kinematic behavior of the causative fault and the surrounding stress field. The systematic collection of coseismic surface rupture data is therefore essential for reconstructing earthquake rupture processes. For historical earthquakes that lack instrumental records, such observations can also be used to estimate earthquake magnitudes and to constrain the location and geometry of the causative fault. At the same time, coseismic fault displacement represents a localized source of hazard associated with surface-rupturing earthquakes, as it can directly affect settlements, infrastructure, and the landscape. By documenting the physical impact of surface faulting on both the natural environment and the built environment, SFIT provides an important resource for seismic hazard assessment and for improving the mitigation of risks associated with future surface-faulting earthquakes. The database can also be a reference for rapid scientific surveys during seismic emergencies, particularly for field teams operating on the ground, such as those involved in the long-standing Emergeo Working Group coordinated by INGV.

SFIT is designed as a living resource and will be progressively updated through new releases that incorporate additional events and datasets, ensuring its long-term value for both the scientific community and stakeholders involved in seismic risk management.

coseismic rupture Norcia 2016 — Principal coseismic rupture on unconsolidated terrain produced by the 2016 Norcia earthquake. Credit: INGV.

surface rupture Etna 2018 — Surface faulting affecting the paved courtyard and fence wall produced by the 2018 Etna-Fleri earthquake. Mount Etna volcano
in the background. Credit: INGV.

Details: Category: datasets

pdf-italy

PDF-Italy methodological approach

The Probability map of distributed faulting in Italy was obtained by combining information derived from two public databases: the DISS database (https://diss.ingv.it/), which is a geospatial repository of seismogenic sources, i.e. major active faults capable of generating damaging earthquakes and widely used in seismic hazard assessment, and the ITHACA database (https://sgi.isprambiente.it/ithacaweb/default.aspx#1) that collects available information on active and capable faults affecting the Italian territory, based on a critical review of the available literature.
In order to estimate the probability that a capable fault from the ITHACA database produces surface ruptures following earthquakes generated by the seismogenic sources of the DISS database, the elements of the two datasets are integrated into a system of principal and distributed faulting, a framework commonly adopted in coseismic surface faulting hazard studies. Specifically, the upper tip of the CSS seismogenic sources of DISS are treated as principal faults along which primary faulting occurs. Conversely, the capable faults from the ITHACA database are assimilated into distributed faulting phenomena that develop in association with primary faulting. The resulting probabilities are conditional probabilities of distributed faulting occurrence given the occurrence of an earthquake on the associated seismogenic source. They do not represent time-dependent probabilities and therefore should not be interpreted as the probability that fault rupture will occur within a specified time interval.
The selection of models for estimating the conditional probability of distributed faulting occurrence was guided by: (i) their compatibility with the methodological approach developed for the DISS–ITHACA interoperability; (ii) the updated status of the reference databases adopted; and (iii) the consistency of each model’s applicability range with the Italian seismotectonic setting. Consequently, for each kinematic style, the most recent model consistent with this framework was selected: for normal faults, we selected the model by Ferrario and Livio (2021), whereas for reverse and strike-slip faults, the models by Takao et al. (2014) were adopted.

Ferrario, M. F., and Livio, F. (2021). Conditional probability of distributed surface rupturing during normal‐faulting earthquakes. Solid Earth, 12(5), 1197–1209. https://doi.org/10.5194/se-12-1197-2021.
Takao, M., Ueta, K., Annaka, T., Kurita, T., Nakase, H., Kyoya, T., & Kato, J. (2014). Reliability improvement of probabilistic fault displacement hazard analysis. Journal of Japan Association for Earthquake Engineering, 14(2), 2‐16–2‐36. https://doi.org/10.5610/jaee.14.2_16.

PDF-Italy attributes description

Definition of the PDF-Italy1.0:zone_tszNNN table attributes. These attributes are the same in the distributed file and WFS service.


Field	Variable	Unit	Description
PDF-IT_ID	Integer	n.a.	Identifier of the polygon.
Lat_WGS84	Float	Degrees	Latitude of the center of the polygon.
Lon_WGS84	Float	Degrees	Longitude of the center of the polygon.
DISS_ID	String	n.a.	Identifier of the CSS vertex that is the primary contributor of the conditional probability for that polygon.
Distance	Float	Km	Distance in kilometers to the specific CSS vertex that is the primary contributor of the conditional probability for that polygon.
n_contrib	Integer	n.a.	Total number of the CSS vertices contributing to the aggregated conditional probability of distributed faulting calculated on the center of the polygon.
Ptot	Float	n.a.	Aggregated conditional probability of distributed faulting calculated on the center of the polygon.
Ptot_n	Float	n.a.	Normalized total probability obtained dividing the total aggregated probability of distributed faulting by the number of contributing CSS vertices.

Definition of the ITHACA_PDFtot table attributes. These attributes are the same in the distributed file and WFS service.

Field	Variable	Unit	Description
Vert_ID	String	n.a.	Identifier of the ITHACA vertex.
ITHACA_ID	Integer	n.a.	Identifier of the ITHACA fault.
Lat_WGS84	Float	Degrees	Latitude of the ITHACA vertex (EPSG:4326).
Lon_WGS84	Float	Degrees	Longitude of the ITHACA vertex (EPSG:4326).
DISS_ID	String	n.a.	Identifier of the CSS source that is the primary contributor of the conditional probability for that ITHACA fault.
Distance	Float	Km	Distance in kilometers to the specific CSS vertex that is the primary contributor of the conditional probability for that ITHACA fault.
n_contrib	Integer	n.a.	Total number of the CSS vertices contributing to the aggregated conditional probability of distributed faulting calculated on the ITHACA fault vertex.
Ptot	Float	n.a.	Aggregated conditional probability of distributed faulting calculated on the ITHACA fault vertex.
Ptot_n	Float	n.a.	Normalized total probability obtained dividing the total aggregated probability of distributed faulting by the number of contributing CSS vertices.

Definition of the Index-map table attributes. These attributes are the same in the distributed file and WFS service. CRS: EPSG 4326 - WGS84.

Field	Variable	Unit	Description
ZONE_ID	String	n.a.	Identifier of the area.
AREAKM2	Real	km2	Surface of the area.
Zone_WFS_URL	String	n.a.	URL of the WFS layer

Details: Category: datasets

sfit

**Definition of the SFIT table attributes. These attributes are the same in the distributed file and WFS service.**

**Point Data:** This layer includes coseismic rupture observation points related to different surface faulting earthquakes. Each point includes detailed information about the coseismic feature: its location, typology, geometry, type and size of movement, a brief description, related images, and the data source. Each point is linked through a code to the rupture line to which it belongs. Where specific attributes were not reported in the original datasets, the corresponding fields are intentionally left empty.
Field	Variable	Unit	Description
ID_POINT	integer	n.a.	identifier of the point.
ID_INTEROPERABILITY		n.a.
ID_ETQ	string	n.a.	earthquake reference code with date and time from CPTI https://doi.org/10.13127/cpti/cpti15.4
NAME_ETQ	string	n.a.	common name of the earthquake.
LAT_ETQ	double	degrees	epicenter Latitude (DD, WGS84) from CPTI https://doi.org/10.13127/cpti/cpti15.4
LON_ETQ	double	degrees	epicenter Longitude (DD, WGS84) from CPTI https://doi.org/10.13127/cpti/cpti15.4
MAG_ETQ	double	n.a.	moment magnitude from CPTI https://doi.org/10.13127/cpti/cpti15.4
Kinematics_ETQ (short name: K_ETQ)	string	n.a.	Earthquake Kinematics: N (normal), T (reverse), SR (dextral strike-slip), SL (sinistral strike-slip), NSR (Normal with Right Lateral component) etc.; generally from focal mechanisms.
ID_POINT_O	integer	n.a.	identifier of the original point in the data source. When missing or not in a suitable format, it is assigned by the compilers.
LAT_POINT	double	degrees	point Latitude (DD, WGS84).
LON_POINT	double	degrees	point Longitude (DD, WGS84).
ELEV_POINT	double	meter	altitude of the point a.s.l.
OBS_TYPE	string	n.a.	coseismic rupture, coseismic warping, coseismic liquefaction, panoramic view (when the point represents the location from where a panoramic photo is taken), Dummy point (artefact to draw a rupture line with no observation points).
Hangingwall Substratum (short name: HW_Subs)	string	n.a.	description of the type of hangingwall substratum – when, in the original dataset, it is not specifically defined for the hangingwall, we use the generic field substratum.
Footwall Substratum (short name: FW_ Subs)	string	n.a.	description of the type of footwall substratum – when, in the original dataset, it is not specifically defined for the footwall, we use the generic field substratum.
Strike	double	degrees	direction of the rupture (right-hand rule).
Dip Angle	double	degrees	angle of dip along the dip direction/perpendicular to the strike.
Dip Direction (short name: Dip Dir)	double	degrees	measured along the dip direction of the rupture.
Length (m) (short name: Len_m)	double	meter	length of the rupture.
Kinematics (short name: K)	string	n.a.	Kinematics of the rupture: O (opening), N (normal), T (reverse), SR (dextral strike-slip), SL (sinistral strike-slip), NSR (Normal with Right Lateral component), etc.
Throw (cm) (short name: Th_cm)	double	centimeter	average vertical separation between hanging wall and footwall.
Throw_min (cm) (short name: Th min_cm)	double	centimeter	minimum vertical separation between hanging wall and footwall.
Throw_max (cm) (short name: Th max_cm)	double	centimeter	maximum vertical separation between hanging wall and footwall.
Lateral offset (cm) (short name: LOf_cm)	double	centimeter	average lateral separation along the strike.
Lateral offset_min (cm) (short name: LOf min_cm)	double	centimeter	minimum lateral separation along the strike.
Lateral offset_max (cm) (short name: LOf max_cm)	double	centimeter	minimum lateral separation along the strike.
Opening (cm) (short name: O_cm)	double	centimeter	average horizontal separation (opening) between the two sides of the rupture.
Opening_min (cm) (short name: O min_cm)	double	centimeter	minimum horizontal separation (opening) between the two sides of the rupture.
Opening_max (cm) (short name: O max_cm)	double	centimeter	minimum horizontal separation (opening) between the two sides of the rupture.
Vertical Warping (cm) (short name: VWarp_cm)	double	centimeter	average height of the warp.
Vertical Warping_min (cm) (short name: VWarp min)	double	centimeter	minimum height of the warp.
Vertical Warping_max (cm) (short name: VWarp max)	double	centimeter	maximum height of the warp.
Horizontal Warping (cm) (short name: HWarp_cm)	double	centimeter	average measure of the entity of the warp.
Horizontal Warping_min (cm) (short name: HWarp min)	double	centimeter	minimum measure of the entity of the warp.
Horizontal Warping_max (cm) (short name: HWarp max)	double	centimeter	maximum measure of the entity of the warp.
Net slip (cm) (short name: Nslip_cm)	double	centimeter	net slip along the slip vector.
Slip Vector Trend (short name: SVe_Trend)	double	degrees	direction of the slip lineation, measured clockwise with respect to the north (range 0°-360°).
Slip Vector Plunge (short name: SVe_Plunge)	double	degrees	plunge of the slip lineation in degrees, measured with respect to the horizontal (range 0°-90°).
Rake	double	degrees	angle of the slip lineation on the fault plane measured in degrees (in the 0°-180° range)
Fracture Zone Width (short name: FZ_Width)	double	meter	width of the fracture zone across the average fault strike at the point.
Start/End/Middle/Central point (short name: S_E_M_C_pt)	string	n.a.	definition of point as start (S), end (E), Middle (M), Central (C) of the rupture line (ID_LINE_OR).
idTrace	integer	n.a.	identification number of the original line including the point.
ID_PHOTO	string	n.a.	labels of the photos related to the point from the data source.
PHOTO_Credits (short name: PH_CRS)	string	n.a.	additional information on the observation point.
NOTE	string	n.a.	additional information on the observation point.
References (short name: REF)	string	n.a.	citation of the source of the data (doi).
Author_ranking (short name: Ranking)	integer	n.a.	ranking code for the significance of the feature according to the original authors: 1) principal fault ruptures, representing the surface expression of the fault responsible for the earthquake and including all the ruptures along faults that are connected to the principal fault at depth; 2) unpredictable distributed ruptures, ruptures also distant not necessarily connected to the principal fault; 3) triggered rupture along a pre-existing fault that is not directly connected to the principal fault, or along a shallow structure that is located within the coseismic deformation area; 4) ground shaking or shaking/gravity-induced rupture. Blank when no interpretation from the data source is provided. The ranking categories mostly follow the rationale defined in SURE 2.0 database (doi.org/10.1038/s41597-022-01835-z).

**Definition of the SFIT table attributes. These attributes are the same in the distributed file and WFS service.**

**Line Data**: The layer displays the traces of the surface ruptures associated with the earthquake. Each trace may contain information about the geometrical and kinematics characteristics, and the data source. Where specific attributes were not reported in the original datasets, the corresponding fields are intentionally left empty. Traces may include one or multiple observation points and can be represented in different ways depending on the original data available in the data source.
Field	Variable	Unit	Description
ID_LINE	integer	n.a.	identifier of the rupture line.
ID_INTEROPERABILITY		n.a.
ID_ETQ	string	n.a.	earthquake reference code with date and time from CPTI https://doi.org/10.13127/cpti/cpti15.4
NAME_ETQ	string	n.a.	common name of the earthquake.
LAT_ETQ	double	degrees	epicenter Latitude (DD, WGS84) from CPTI https://doi.org/10.13127/cpti/cpti15.4
LON_ETQ	double	degrees	epicenter Longitude (DD, WGS84) from CPTI https://doi.org/10.13127/cpti/cpti15.4
MAG_ETQ	double	n.a.	moment magnitude from CPTI https://doi.org/10.13127/cpti/cpti15.4
K_ETQ	string	n.a.	Earthquake Kinematics: N (normal), T (reverse), SR (dextral strike-slip), SL (sinistral strike-slip), NSR (Normal with Right Lateral component) etc.; generally from focal mechanisms.
idTrace	integer	n.a.	identifier of the original rupture line in the data source. When missing or not in a suitable format, it is assigned by the compilers.
OBS_TYPE	string	n.a.	coseismic rupture, coseismic warping, coseismic liquefaction.
Length (m) (short name: Len_m)	double	meter	length of the line.
Orientation (short name: Orient)	integer	degrees	average strike of the trace, in degrees (right-hand rule).
Kinematics (short name: K)	string	n.a.	Kinematics of the rupture: O (opening), N (normal), T (reverse), SR (dextral strike-slip), SL (sinistral strike-slip), NSR (Normal with Right Lateral component), etc.
Downthrown side (short name: Downside)	string	n.a.	cardinal direction of the downthrown side of the rupture.
Vertical Offset (cm) (short name: VOf_cm)	double	centimeter	average vertical separation between hanging wall and footwall.
Vertical Offset_min (cm) (short name: VOf min_cm)	double	centimeter	minimum vertical separation between hanging wall and footwall.
Vertical Offset_max (cm) (short name: VOf max_cm)	double	centimeter	maximum vertical separation between hanging wall and footwall.
Lateral Offset (cm) (short name: LOf_cm)	double	centimeter	average lateral separation along the strike.
Lateral Offset_min (cm) (short name: LOf min_cm)	double	centimeter	minimum lateral separation along the strike.
Lateral Offset_max (cm) (short name: LOf max_cm)	double	centimeter	maximum lateral separation along the strike.
Opening (cm) (short name: O_cm)	double	centimeter	average horizontal separation (opening) between the two sides of the rupture.
Opening_min (cm) (short name: O min_cm)	double	centimeter	minimum horizontal separation (opening) between the two sides of the rupture.
Opening_max (cm) (short name: O max_cm)	double	centimeter	maximum horizontal separation (opening) between the two sides of the rupture.
LAT_Central_POINT (short name: LAT_C_PT)	double	degrees	latitude of the central point of the line (decimal degrees, WGS84).
LON_Central_POINT (short name: LON_C_PT)	double	degrees	longitude of the central point of the line (decimal degrees, WGS84).
ID_Start POINT (short name: ID_S_PT)	integer	n.a.	original identifier of starting point of the line identifier.
ID_Middle POINT (short name: ID_M_ PT)	integer	n.a.	original identifier of middle point of the line identifier.
ID_Central POINT (short name: ID_C_PT)	integer	n.a.	original identifier of central point of the line identifier.
ID_End POINT (short name: ID_E_PT)	integer	n.a.	original identifier of ending point of the line identifier.
Uncertainty (short name: Unc)	string	n.a.	observed or inferred line.
Note	string	n.a.	additional information on the line.
References (short name: REF)	string	n.a.	citation of the source of the data (doi).
Author_ranking (short name: Ranking)	integer	n.a.	ranking code for the significance of the feature according to the original authors (1) principal fault ruptures, representing the surface expression of the fault responsible for the earthquake and including all the ruptures along faults that are connected to the principal fault at depth; 2) unpredictable distributed ruptures, ruptures also distant not necessarily connected to the principal fault; 3) triggered rupture along a pre-existing fault that is not directly connected to the principal fault, or along a shallow structure that is located within the coseismic deformation area; 4) ground shaking or shaking/gravity-induced rupture. Blank when no interpretation from the data source is provided. The ranking categories mostly follow the rationale defined in SURE 2.0 database (doi.org/10.1038/s41597-022-01835-z).

Details: Category: datasets

sfit

For further information about the dataset

Francesca Romana Cinti

Istituto Nazionale di Geofisica e Vulcanologia
Via di Vigna Murata, 605 - 00143 Roma, Italy
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
https://orcid.org/0000-0003-1068-3223

Daniela Pantosti

Riccardo Civico

For further information about the web services

Roberto Vallone
Istituto Nazionale di Geofisica e Vulcanologia
Via di Vigna Murata, 605 - 00143 Roma, Italy
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
http://orcid.org/0000-0003-1208-9412