#1EGU Gerely 2020 EGU2020-18656 Online | 4-8 May 2020 Ten years of civil protection support activities in landslide areas of Basilicata (southern Italy) Angela Perrone Institute of Methodologies for Environmental Analysis (IMAA) Italian National Research Council (CNR)#2Landslide risk management ✓ Civil protection system (CPS) is initially activated to response to the emergency ✓ CPS involves: 1) Civil Protection Departments at national (DPC) and regional (DRPC) levels, 2) scientific institutions (namely Competence Centres - CdCs), 3) local admministration personnel and technicians. ✓ Institute of Methodologies for Environmental Analysis (IMAA) of Italian National Research Council (CNR) is one of the CdCs that collaborates with DPC and DRPC in landslide emergency#3Main questions Information needed in the emergency phase . What was the trigger factor? . . How extensive the landslide body is? What is the displacement velocity? How deep the sliding surface is? How much material was involved in the movement? Are there any areas that could be affected by future instability phenomena? .? ? The cooperation of Competence Centres allows DPC or DRPC to exploit all the scientific skills and the state-of-art of investigation technologies to answer these questions in order to plan the first interventions and to size the safety measures#4The support activity of IMAA-CNR to the Basilicata DPC in the landslide emergencies of the last ten years Date of event Kind of event From 18/02/2011 to 01/03/2011 Flood 26/10/2012 Territory involved Jonian coast Earthquake Pollino area (southern of Basilicata) From 7/10/2013 to 8/10/2013 Flood Bernalda, Pisticci, Scanzano From 01/12/2013 to 03/12/2013 Flood and landslide From 05/01/2017 to Heavy snow First activation: Landslide February 2014 Worsening of conditions: 18/01/2017 December 2017 First activation: 25/01/2019 Second activation: 29/01/2019 Montescaglioso, Jonico (all towns are located in Matera territory) Territory of Potenza and Matera Province; Montescaglioso area Different portion of Basilicata region Urban area of Stigliano (Matera) Ordinance or Date of ordinace or delibaration deliberation Ordinance of the President of the Council of Ministers n.3984 25/11/2011 Ordinance of the Head 20/11/2012 of the Civil Protection Department n.25 Ordinance of the Head 8/02/2014 of the Civil Protection Department n.145 Ordinance of the Head 21/02/2014 of the Civil Protection Department n.151 Deliberation of the Council of Ministers Deliberation of the Council of Ministers Landslide Urban area of Pomarico (Matera) Deliberation of the Council of Ministers 16/06/2017 29/12/2017 14/02/2019 In the last ten years Basilicata region has been affected by significative landslide phenomena, occurring after extreme rain events. The phenomena mainly affected the hilly area of Matera and in particular the towns of Montescaglioso, Stigliano and Pomarico. The emergency state was declared after each of these events has occurred. Geophysical Laboratory of IMAA-CNR has supported the DRPC by applying in situ geophysical techniques with the aim to provide a geophysical model useful to reconstruct the geological setting of the subsoil, to identify the sliding surface and to locate high water content areas.#5Bradanic trough Apenninic chain Vesuvio Lithology and landslides distribution in Basilicata region Adriatic Sea N Bari Apulian foreland asso di Castalda Craco SG. Tyrrhenian Sea Eolian Islands TA Taranto Gulf Calabrian trench Ionian Sea 100km Modified by Bentivenga et al., 2017 Bradanic Trough and piggy-back or intramontane basin infills Apenninic units Calabrian units APULIA Lavello Melfi Rionens Veama Apulian platform Maro Lucano Irina Pleistocene or active Volcanoes Avigliano Potenza Front of the apenninic nappes Fluvio-lacustrine plains Coastal and terraced areas Bradanic Trough and Sant'Arcangelo Basin Fluvio-karst and ravine of Matera Murgia Arenaceous terrains of the Apenninic chain Pliocene intrachain basins Volcaninc area Clayey terrains of the Apenninic chain Silico-calcareous terrains of Apenninic chain Calcareous terrains of Apenninic chain Sogliano Apulian platform margin Corlet CAMPANIA Forebulge axis (SG) Sangineto and (TA) Taormina tectonic lines Maratea A Tyrrenhian sea A r Trace of the cross-section Lagonegro CALABRIA Modified by Lavecchia et al., 2003 Matera Policoro Metaponto lonian sea 10 km#6Landslide • Pre-event borehole Post-event borehole HV06 ERT4 Ambient seismic noise measurement ERT HV11 Google Earth HV13 SHV14 Se HV15 St $9 ERT3 STO HV09 HV12 HV04 Susa ERT2 HVA ERT1 Montescaglioso landslide: December 2013 HV08 ERTO V02 HVOZ 500 m Kind of measure Action Number of action Date Ordinance Interdiction to access in 2 landslide area 3th December 2013 Ordinance Evacuation of buildings in 17 landslide area 3th December 2013 Ordinance 3th December 2013 Ordinance Trigger factor: rainfall (rain gauge station of Ginosa 8 km east) Cumulative rain Starting date and local time Ordinance Ending date and local time (mm) Inspection 246.4 6th of October 2013 at 00:00 9th of October 2013 at 11:00 157.6 30th of November 2013 at 13:00 3rd of December 2013 at 2:00 annexes Evacuation of residential 16 units and (deposits, garages, etc.) Evacuation of commercial 8 units and annexes (offices, yards, parking, etc.) Evacuation of residential 4 units (13 people) Technical and structural 33 checks of buildings and infrastructures: n.17 eviction orders n.16 under observation 3th December 2013 3th December 2013 Starting from the 3th of December 2013#7ERT1 Elev. 220.0- 200.0 180.0- 160.0- 140.0 Montescaglioso landslide: comparison between ERT, HVSR and stratigraphical data HV13 ERTO (a) Model resistivity with topography Elev 240.0 Iteration 3 RHS error -11.9 220.0 Sands and gravel silty Conglomerates SHV14 CS HV07 hent HV15 R13 HV09 HV12 Sust HVO ERT2 HV10 Model resistivity with topography Iteration 3 RMS error 4.2 0.0 Landslide boundary 120.0 100.0 80.0- SW 2.00 4.00 8.00 16.0 St-S9 ERT1 V02 HVSR01 8 8 Average H Sid Dev 6 M 4 2 6 W 4 2 HVSR02 200.0- ERTO 180.0- Clays S8 reprojected 800.0 640.0 480.0 320.0 ST-S6 160.0- 160.0 ST-S5 149.8 0.0 ST-S11 120.0- 100.0- 80.0 60.0 40.0- SW 20.0 2.00 4.00 8.00 16.0 32.0 Resistivity in ohm.m 64.0 128 256 8 HVSR04 6 Average H/W HVSR09 Average H/V HVSR05 Std Dev Std.Dev. Average HV Std Dev (b) Model resistivity with topography Iteration 3 RMS error = 7.3 4 2 10 frequency [Hz] HVSR09 320.0 ST-S6 10 Elev. 200.0 frequency [Hz] 180.0 HVSR04 ERT2 160.0- 160.0 ST-S5 140.0.0.0 ST-S11 120.0 100.0- Average HV SW Std. Dev. 80.0- S6 60.0- 2.00 4.00 8.00 16.0 32.0 Resistivity in ohm.m 64.0 128 256 ° 0 1 10 1 10 frequency [Hz] frequency [Hz] HVSR02 Landslide boundary 640.0 HVSR01 320.0 S5 160.0 32.0 64.0 Resistivity in ohm.m 128 256 480.0 Silty clay Clays NE frequency [Hz] 480.0 10 HVSR05 640.0 Geophysical measurements n. 5 Electrical resistivity tomographies (ERT) n. 15 Ambient seismic noise measurements (HVSR) S8 NE NE#8Boreholes Electrical resistivity tomography Ambient seismic noise measurement Stigliano landslide: February 2014 ERT2 ERT1 HVSR2 HVSR Via Cilento Kind of measure Ordinance n.3 Ordinance n.4 Action Date Partial eviction of things and people from 20th January 2015 the Social Center Total eviction of things and people from 26th January 2015 the Social Center Ordinance n.68/74 N.6 families were evacuated from the 6th July 2017 buildings located in Via Cilento from n.1 to n.17 Fontana Trench Carpino Trench Trigger factor: rainfall Date Rain gauge station Cumulative rain (mm) Time (h) Photo by Civil Protection Basilicata region Photo by Civil Protection Basilicata region 5th 7th October 2013 Gorgoglione 50.60 72 5th 7th October 2013 San Mauro Forte 26.60 72 11th 13th November 2013 Gorgoglione 98.40 72 11th-13th November 2013 San Mauro Forte 107.60 72 30th November - 2nd December 2013 Gorgoglione 164.40 72 30th November - 2nd December 2013 San Mauro Forte 191.20 72 1st-3rd February 2014 Gorgoglione 124.40 72 Photo by Civil Protection Basilicata region Photo by Civil Protection Basilicata region 1st-3rd February 2014 San Mauro Forte 97.20 72#9ana Trench 63 Cilento M Stigliano landslide: comparison between ERT and HVSR ERTZ ERTI 51 54 8 HVSR1 7 6 5 4 3 0.1 HVSR2 HVSR Via Cilento Elev. 920.0 0.0 915.0 910.0 905.0 980.0 895.0 Hodel resistivity with topography Iteration 4 RHS error = 7.6 890.0 NW Max. H/V at 1.25 ± 0.47 Hz (in the range 0.0 - 64.0 Hz). 10 frequency [Hz] HVSR1 64.0 32.0 5.00 10.0 20.0 40.0 80.0 Resistivity in ohm.m 160 320 640 ERT1 128.0 96.0 Geophysical measurements n. 2 Electrical resistivity tomographies (ERT) n. 2 Ambient seismic noise measurements (HVSR) Average HW N-S/V E-W/V H/V SE#10Pomarico landslide: January 2019 Date Eviction of n.14 residential and 25th January 2019 commercial units; traffic closure of Corso Vittorio Emanuele. 631150 631200 631250 631300 631350 City of Pomarico Kind of measure Ordinance n.1 Action ERT 1 S1 4486350 4486300 4486250 4486200 V SERT_2 WXERT 3 4485950 4485900 4485850 360 4485800 HVSR GPR ERT MASW SRT S Ordinance n.2 Ordinance n.6 Eviction of n.11 residential and 26th January 2019 commercial units. Eviction of n.27 residential 30th January 2019 units; traffic ban in Salita S. Rocco up to the intersection with Spartivento road and Castello Quarter. Scala 1:2000 0 50 100 m S4 630800 630850 630900 630950 631000 Date Trigger factor: rainfall Rain gauge station Cumulative Time rain (mm) 24th-26th January 2019 Matera 42 mm 48 hours 24th-26th January 2019 Torre Accio - Bernalda 55 mm 48 hours Photo by Civil Protection Basilicata region#11Comune di Pomarico ERT 1 Via San Rocco Pomarico landslide: comparison between ERT, MASW and stratigraphy Via San RocCO Elev. 430.0 420.0 Corso Vittorio Emanuele 410.0-0.0 400.0 Via Spartivento Model resistivity with topography Iteration 5 RHS error -6.0 390.0 380.0 NW Elev. 440.0 ERT1 S1 200.0 Old landslide boundary? 160.0 120.0 80.0 40.0 2.00 4.50 10.1 22.8 51.3 115 Recictiuitu in nha.m 259 584 Model resistivity with topography Iteration 5 RMS error 4.8 430.0 80.0 40.0 420.0 0.0 410.0 400.0 390.0 NW 2.00 4.50 10.1 22.8 51.3 115 Resistivity in ohn.n 259 584 ERT2 120.0 MASW4 160.0 308 m/s 375 m/s 424 m/s Landfill Sands Sandy silts Blue-gray clayey silts 200.0 SE Old landslide boundary? Geophysical measurements n. 3 Electrical resistivity tomographies (ERT); n. 4 Multichannel Analysis of Surface Waves (MASW) n. 1 Seismic refraction tomography (SRT); n. 20 Ambient seismic noise measurements (HVSR); 810 m georadar profiles (GPR) SE#12Final remarks Geophysical techniques, being less invasive and more expeditious than direct techniques (especially geotechnical), prove to be particularly suitable during the landslide emergency phase. Geophysical techniques are easily applicable to investigate landslides occurred in rural areas. Geophysical techniques can be affected by applicability problems in the study of landslides that affect urban areas. In these areas, the integration of different geophysical techniques along the same profiles can help to obtain a large amount of information, improving the interpretation and the significance of the results.