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 |
