NSFGEO-NERC: The central Apennines earthquake cascade under a new microscope

Lead Research Organisation: NERC British Geological Survey
Department Name: Earth Hazards & Observatories

Abstract

Three strongly felt earthquakes of magnitude M>5.9 occurred within a 50 km source zone along the Central Apennines mountain chain in a period of just over 2 months. The first, on the 24th August M=6.0 earthquake killed 297 people, leaving the medieval villages of Amatrice, Accumoli and Pescara di Tronto devastated. On 26th October two large shocks of M=5.4 and M=5.9 (32 minutes after) struck ~30 km further north in the same region as the 1997 M=6.0 Colfiorito earthquake. The largest (M=6.5) event to date that occurred only four days later, on 30th October, caused severe damage to buildings at Norcia, including the historical cathedral of San Benedetto. The area has been struck by destructive earthquakes of significant magnitude in historical and modern times. This is the third catastrophic sequence to occur in the Central Apennines, with preceding sequences to the north (M=6.0 Colfiorito) and south (M=6.1 L'Aquila) in 1997 and 2009, respectively. Cultural heritage sites including word-famous medieval churches near Amatrice village, have suffered severe damage and total collapse in many cases.

Within this post-disaster environment there is a clear need to improve our understanding behind the evolution of such sequences and to develop tools that can support informed decision-making in the future. Our research will be based on a unique high quality dataset that is a product of on-going UK-Italian collaboration involving the deployment of more than 85 seismic sensors at the affected area since last fall. This unprecedented observational capability enables us to capture the "breadth and depth" of seismicity leading to the large events within the sequence. Based on this dataset we will develop innovative methods to translate measurements into testable physical models for the underlying processes. We aim at developing a comprehensive earthquake catalog that includes precise locations, source parameters and focal mechanisms derived from algorithms that are able detect, locate and characterize even the smallest events. This new 'microscope' provides information that is crucial for unravelling the physical processes that underlie sequences such as the extended 2016 Amatrice/Norcia earthquakes in Italy. We will then use the high-accuracy catalog to formulate and test alternative earthquake triggering hypotheses and integrate those in the development and validation of testable forecast models using empirical and physics based models to ensure high predictability.

The project brings together world-experts on earthquake detection, seismic source characterization, earthquake triggering and forecasting from US, UK and Italy in an effort to develop breakthrough approaches to address current challenges that not only impede our understanding behind earthquake processes but also weaken our scientific response in any post-earthquake disaster environment. In the course of our research we will involve further international initiatives such as CSEP (Collaboratory for the Study of Earthquake Predictability) to ensure transparent testing of our forecast models, and EPOS (European Plate Observation System) to maximize knowledge exchange and the scientific impact of the project in other countries. The new observational capability to detect, locate and characterize even the smallest magnitude events within few hours will find application to induced, geothermal and volcanic activity areas in US and Europe. We anticipate that the application of our research framework especially in high seismic hazard sites worldwide will enable future decision making with the same scientific standards across different operational and cultural environments.

Planned Impact

The primary aim of this NSFGEO-NERC proposal is the exploration of the physics in complex earthquake sequences by producing high resolution earthquakes catalogs and using those to develop and test increasingly sophisticated earthquake forecasting models. While our focus remains on discovery science, there are only few areas of solid earth science which have more resonance with the needs of stakeholders in earthquake prone regions worldwide or in areas prone to seismicity induced by industrial activity. Currently, the possibility of providing relevant forecasts of earthquake activity during a sequence and the operational management of induced seismicity is the subject of several research activities worldwide including important initiatives led by members of this team. The team includes members of organisations, such as INGV, BGS and USGS, with statutory responsibility for providing scientific information during emergencies and whose data and analyses are used to advise earthquake response worldwide. We have direct operational links with international NGOs, and a strong track record of engagement with the media worldwide. The current NSFGEO-NERC proposal has clear and immediate Pathways to Impact through these networks with which they are already fully engaged.

The team contribute to active NERC and NSF funded projects on operational issues of earthquake science which will directly benefit from the results of this project. We have direct influence in key government stakeholder organisations with global reach. The project lead, BGS, has a statutory responsibility to provide information to the UK Cabinet Office and the Foreign and Commonwealth Office during emergencies and are the main conduit for scientific advice to the UK government on the potential for induced seismicity due, for example, to fracking. The USGS is responsible for short-term earthquake advisories in the United States and the Southern California Earthquake Centre, with co-director Beroza (co-I here), has recently implemented forecast models which will be enhanced by the science planned in this project.

The INGV is the authoritative organization for the seismic and the volcanic monitoring in Italy and is directly involved in scientific communication to citizens. Moreover, the Seismic Hazard Centre (CPS; co-chaired by Marzocchi) is the INGV appointed group for releasing information on seismic hazard and earthquake forecasts to the Civil Protection agency.

The project results will be reported directly to several international NGOs, all of which are emergency responders following earthquakes and have on-going projects lead by members of this team. The entire project team has a strong record of interaction with the media and we will ensure regular press releases to inform the public of progress in this breakthrough project. It is our intention to host three outreach events in the UK, US and culminating with an international workshop hosted at INGV Rome. Finally, the team includes researchers and professors at leading universities and institutes in Europe and the US who will ensure that the project creates outstanding training opportunities for early career researchers and that its results are immediately reflected in the curricula of important graduate and undergraduate programs in natural Hazards sciences.

Publications

10 25 50