Marco Mulas

COSMO SkyMed high frequency - high resolution monitoring of an alpine slow landslide, corvara in Badia, Northern Italy

Located in the Alta Badia Valley, a famous tourist area in the Dolomites of northern Italy, the active Corvara earthslide-earthflow causes damages to critical road infrastructures, as well as ski and other recreational facilities and power lines. The high spatial resolution and the short frequency of revisit time of COSMO-SkyMed system (CSK®), open new opportunities for SAR-based monitoring systems dedicated to natural risks management. The ASI AO funded project “LAWINA” takes advantage from these distinctive features together with non-conventional reflectors, in order to monitor and assess the hazard of such a phenomenon by means of PSI techniques. The particular working context and the complete processing workflow for this specific application, offer opportunity to highlight strengths and weak points of classical approach to PSI and to provides suggestions for an effective use of experimented corners.

Assessment of the 2006 to 2015 Corvara landslide evolution using a UAV-derived DSM and orthophoto

We present a UAV-based photogrammetry study on Corvara landslide, a large and active earthflow in the Italian Dolomites. During a one-day field survey, an area of approximately 13 ha was covered and a very high resolution orthophoto and a point cloud consisting of more than 200 million points were created. From this data, a Digital Surface Model (DSM) with a pixel size of 1.5 cm was prepared. The comparison to the existing 2006 LiDAR DSM highlights landslide enlargements, displacement rates and material depletion and accumulation exceeding 11 m. Although some uncertainties regarding the exact magnitude of topographical changes remain, the methodology has been evaluated as a useful addition to the ongoing monitoring activities on the Corvara landslide by GPS and DInSAR due to the unprecedented level of detail. processed to a point cloud and a Digital Surface Model (DSM). These were then compared to existing data sets to assess the changes over time.

A portable continuous GPS array used as rapid deployment monitoring system during landslide emergencies in Emilia Romagna

The possibility to rapidly deploy a continuous monitoring system in and around an active landslide during an emergency is crucial in order to gather information for hazard and risk scenarios updates. This paper deals with the use of an optimized portable and self-powered array of continuous GPS receivers that has been used for rapid deployment in several landslides during 2013 and 2014 emergency events in Emilia Romagna. In order to optimize the array of GPS receivers, so to make it a sort of plug-and-play system that can be operative in a few hours only and provide data in near-real time,, several technical and logistic issues had to be pre-evaluated and solved in the configuration of the system. These issues are illustrated in the short note together with some of the results obtained in the monitored sites.

Long-term continuous monitoring of a deep-seated compound rock slide in the Northern Apennines (Italy)

An automated total station monitored a compound rock slide near the Cerreto Pass (northern Apennines, Italy) for more than three and a half years. The rock slide, which threatens national road SS63, has an estimated volume of more than 3 million m3 and is composed by the overlap of highly fractured limestone on an impermeable and weak clay shale layer. Specifically, a network of more than 30 prisms has been measured every 2 h from October 2009 to May 2013. This dataset provides substantial evidence of displacement rates up to 15 cm/year and gives information about the control of rainfall on slope movements. On the yearly scale the seasonal variation of rainfall regime determines the baseline displacement rate of the rockslide while moving to shorter time spans has been possible to individuate effects of rain episodes calculated on daily and weekly sampling. Results highlight the added value of continuous monitoring for assessing rock slide dynamics and improving hazard assessment.

Landslide Zoning Using the Principal Component Analysis on Monitoring Data: The Sauna Earth Slide—Earth Flow (Parma, Italy)

In this contribute, we present the morphodynamic zoning of the Sauna complex earth slide—earth flow (Corniglio municipality, Northern Apennines) obtained by integrating results of field surveys and of Principal Component Analysis (PCA) of continuous displacement monitoring data. Since January 2014, the area is surveyed by an Automated Total Station (ATS) monitoring 30 prisms with duty cycles of 2 h. An evacuation plan has been adopted by the local authorities, which is based on pre-defined movement thresholds. However, during more than 2 years of monitoring, the results have evidenced that in different zones of the slope, differentiate displacement rates and timings of response to precipitations take place. Therefore, in order to fine tune evacuation plans, movement thresholds should be more appropriately tailored on the basis of morphodynamic zones rather than being left spatially generic. The final result is a morphodynamic zonation of the slope that represents a useful document to identify areas in which differentiated movement thresholds can be assessed for alert and alarm.

Quantitative monitoring of surface movements on active landslides by multi-temporal, high-resolution X-Band SAR amplitude information: Preliminary results

Multi-temporal image cross-correlation is a method for tracking moving features and can there-fore be used for quantitative assessments of surface displacements. Accuracies of up to 1/8th of the original image geometric resolution can be achieved. We present the results of an analysis carried out on Corvara landslide located in the Italian Dolomites. Image offset-tracking was applied to CosmoSky-Med amplitude images acquired between October 2013 and August 2015. The presence of a validation dataset consisting of periodical GPS surveys carried out on 16 benchmarks represents an ideal opportunity to test the applicability of SAR-based image cross-correlation for landslide monitoring. Despite the relative low accuracy of the results amplitude-based offset-tracking proved to be beneficial due to the ability of this method to capture large displacements. In particular the results evidence its complementarity with respect to multi-temporal interferometry that is confined to slow displacements along E-W directions. 2 CASE STUDY AND DATASET 2.1 Corvara landslide Corvara landslide is an active slow-moving landslide located up-slope the homonym village in the Dolomites area (NE Italy). Since it is a widely investigated phenomenon whose geometries have been clearly defined by land surveys and instrumental monitoring (Corsini et al. 1999, Corsini et al. 2001, Corsini et al. 2005), it represents the ideal case study for testing novel monitoring techniques and technologies (Corsini et al. 2012, Mulas et al. 2012, Mulas et al. 2015b). The landslide has been classified as an active, slow-moving deep-seated rotational earthslide-earthflow with active slip surfaces located at depths of up to 48 m. The bedrock of the area consist of weak formations of the Triassic characterized by the alternation between sub meter strata of hard rocks and weak rocks (Corsini et al. 2000). 2.2 SAR and D-GPS dataset Monitoring data collected in the period 2001– 2008 (Corsini et al. 2012) highlight a wide range

Toward a centralized data management center for integrated landslide monitoring in Emilia Romagna Region (Italy)

In Emilia Romagna Region, slope monitoring systems have become more widely used for hazard and risk management. However, they are generally non-interoperable. Moreover dispersion of monitoring data in several local databases have made data sharing among the involved institutional actors quite laborious and often untimely. A centralized database and a web-based portal that integrate information derived by different types of slope monitoring systems has been developed. The paper illustrates the specific features of the developed “SensorNet” and provides examples of its use for visualizing and analyzing in an integrated manner data from different monitoring systems. In perspective it could serve as an every-day operational tool for a timely reporting of landslide monitoring data for surveillance and warning purposes. data access possibility to all the institutional endusers. The idea is to create a data portal similar in principle—but different in technology—to these already available in some other Italian regions, such as for instance Lombardia (see for example ARPA Lombardia—Centro Monitoraggio Geologico. 2015). The development of a landslide monitoring data portal (SensorNet) for the Emilia Romagna Region, was carried out by Lepida SpA, a public owned company that provides data warehousing and services to the public administrations. Technical Basin Services of Regione Emilia Romagna and the University of Modena and Reggio Emilia supported this activity by providing data and by defining the specific functions that had to be implemented in the portal in order to interrogate and visualize data in formats suitable for institutional end-users. The paper illustrates the specific features of SensorNet and provides examples of its usage for visualizing data from different monitoring systems. SensorNet has reached in 2015 a first level of operational development and it now integrates data from different types of monitoring systems deployed on landslides in the Emilia Romagna Apennines.