A Holistic Approach to Study Groundwater-Surface Water Modifications Induced by Strong Earthquakes: The Case of Campiano Catchment (Central Italy)

Abstract

Carbonate aquifers are characterised by strong heterogeneities and their modelling is often a challenging aspect in hydrological studies. Understanding carbonate aquifers can be more complicated in the case of strong seismic events which have been widely demonstrated to influence groundwater flow over wide areas or on a local scale. The 2016–2017 seismic sequence of Central Italy is a paradigmatic example of how earthquakes play an important role in groundwater and surface water modifications. The Campiano catchment, which experienced significant discharge modifications immediately after the mainshocks of the 2016–2017 seismic sequence (Mmax = 6.5) has been analysed in this study. The study area is within an Italian national park (Sibillini Mts.) and thus has importance from a naturalistic and socio-economic standpoint. The research strategy coupled long-period artificial tracer tests (conducted both before and after the main earthquakes), geochemical and discharge analyses and isotope hydrology with hydrogeological cross-sections. This study highlights how the seismic sequence temporarily changed the behaviour of the normal faults which act predominantly as barriers to flow in the inter-seismic period, with water flow being normally favoured along the fault strikes. On the contrary, during earthquakes, groundwater flow can be significantly diverted perpendicularly to fault-strikes due to co-seismic fracturing and a consequent permeability increase. The interaction between groundwater and surface water is not only important from the point of view of scientific research but also has significant implications at an economic and social level.

Reaction of the carbonate Sibillini Mountains Basal aquifer (Central Italy) to the extensional 2016–2017 seismic sequence

“…Tracer tests were run during the pre- and post-seismic period 26 , 37 , 48 . Tracer was released in the Mergani sinkhole (Castelluccio plain, Figs.…”

“…The hydrogeological effects of the extensional 2016–2017 Central Italy seismic sequence (Mw max = 6.5) 34 , 35 , involving the 600 km 2 wide Sibillini Mountains area (Fig. 1 a), were described by many authors 36 , 5 , 7 – 9 , 26 , 37 . A consistent increase of spring and stream discharge of the hydrogeological systems located at the hanging-wall of the activated SW-dipping normal fault system was observed.…”

“…These effects are attributed to an increase of bulk hydraulic conductivity, resulting in the increment of recession coefficients with respect to pre-seismic conditions 36 , 5 , 7 – 9 , to shaking and/or squeezing effects, or to breaching of hydraulic barriers 5 , 37 .…”

Water–Rock Interaction Processes in Tíscar and Larva Active Faults (Betic Cordillera, SE Spain)

“…Fault zones have the capacity to be hydraulic conduits connecting shallow and deep geological environments [1][2][3]. Mineral precipitations along fault zones are usually considered an indication of accentuated groundwater flow through faults, e.g., [4][5][6]. The crystallization of mineral phases in fault areas is controlled by the chemistry of circulating fluid, the characteristics of the fault rocks, and the physical factors present at the time of mineralization.…”

Mitigation measures preventing floods from landslide dams: analysis of pre- and post-hydrologic conditions upstream a seismic-induced landslide dam in Central Italy

“…It is crucial because the peak flow can produce a progressive failure downstream of the landslide dam, often producing large-scale debris flows and floods. After high magnitude earthquakes, the hydrogeological properties of the river catchment-and consequently the river discharge-can increase in a few days due to the water pressure increase in the aquifer and permanent or semi-permanent variations of the properties of the hydrogeological system feeding the river (Rojstaczer et al 1995;Geballe et al 2011;Manga et al 2012;Petitta et al 2018;Sato et al 2000;Di Matteo et al 2020, 2021Valigi et al 2020;Mammoliti et al 2022). In this framework, engineering measures have to be properly designed during emergency phases and inflow diversion can be used when man-made hydraulic facilities (e.g., reservoir or irrigation systems) are available upstream of the dam (Peng et al 2014).…”