Fault motion reversals predating the Mw 6.3 2009 L'Aquila earthquake: insights from synthetic aperture radar data

The millimetre accuracy of Synthetic Aperture Radar (SAR) measurements and related multi-temporal data analyses provide fundamental information on surface displacements caused by strong earthquakes. The multi-temporal analysis of SAR interferometry data allows for the geometry, kinematics and temporal behaviour of earthquake-generating faults to be better constrained, and is being acknowledged as a promising technique in the field of earthquake precursors. We used SAR data obtained by multi-temporal interferometric techniques such as Permanent Scatterers (PS) interferometry for the investigation of pre- to post-seismic ground displacements in the region struck by the Mw 6.3, 2009 L'Aquila earthquake. We analysed Europen Remote Sensing (ERS) and Envisat PS-datasets from ascending and descending orbits, and COSMO-SkyMed PS-datasets from descending orbit, collectively covering a > 20 year long time span. On a yearly scale, a reversal of motions that affected the hanging-wall and footwall blocks of the earthquake-generating fault is detected. In particular, the hanging-wall block is characterized by pre-seismic uplift – which we document as being independent of any hydrological control – and eastward horizontal motion for about six years, followed by subsidence and westward motion (starting six to eight months prior to the earthquake). We suggest that such a ground displacement pattern may represent an earthquake precursor signal.Supplementary material: Figures showing SAR satellites viewing geometry, examples of raw PS time series of obtained from ERS ascending and descending orbits and maps of LoS-oriented mean velocities obtained from PS datasets from the Envisat ascending and descending orbits and a Table reporting detailed numerical results of the performed statistical analysis are available at https://doi.org/10.6084/m9.figshare.c.5289357

Top-down reconstruction and the failure to “build back better” resilient communities after disaster: lessons from the 2009 L'Aquila Italy earthquake

PurposeWe consider what happened in the initial reconstruction interventions following the 6 April 2009 earthquake in L'Aquila (Italy). Using the disaster risk reduction and resilience paradigm, we discuss the cognitive and interactional failures of top-down approaches, and we analyse the main constraints to enacting inclusive social learning and socially-sustainable transformation and building back better more resilient communities in post-disaster reconstruction.Design/methodology/approachOur evidence comes from participant observation, action anthropology and analytic auto-ethnography conducted during the reconstruction phase following the L'Aquila earthquake. Findings were triangulated with document analysis, media analysis and retrospective interviewing conducted in 2013 and 2017.FindingsThe shift from civil defence to civil protection did not bring any advance in disaster management and development practice in terms of DRR and resilience. The militaristic command-and-control approach, which is still in vogue among civil protection systems, means that local political leaders become the civil protection authorities in a disaster area. As in the L'Aquila case, this exacerbates local social and environmental risks and impacts, inhibits local communities from learning and restricts them from participating in post-disaster interventions.Originality/valueMost previous commentary on disaster recovery and reconstruction following the L'Aquila earthquake has focussed on the top-down approach carried out by the national government and the Italian Department of Civil Protection (DCP). This paper is unique in that it sheds light on how the command-and-control approach was also implemented by local authority figures and on how this undermined building back better more resilient communities.