Aseismic strain episodes at Campi Flegrei Caldera, Italy

Abstract. Since 2004 a research project has been developed to monitor subsurface deformation of Italian volcanoes using borehole strainmeters and long-baseline tiltmeters. Six Sacks-Evertson dilatometers were installed around Campi Flegrei caldera and Vesuvius during 2004–2005 (Scarpa et al., 2007), and in 2008 these instruments were supplemented by two arrays of 28–280 m long water-tube tiltmeters in underground tunnels. Relevant strainmeter and tiltmeter data have been collected and analysed from the instruments installed near Campi Flegrei caldera during the recent unrest episodes. In the period 2004–2005 strain, tilt and GPS data from Campi Flegrei indicate the onset of surface deformation that accompanied a low rate of vertical displacement that continued to 2006, corresponding to an increase of CO2 emission. This strain episode preceded caldera microseismic activity by a few months, as was observed also during a significant inflation episode in 1982. Other transient strain episodes occurred in October 2006, which were accompanied by a swarm of VT (Volcano-Tectonic) and LP (Long Period) events, in 2009, at the time of renewed gas emission activity at Solfatara, and again in March 2010, several minutes before a seismic swarm. The time scale of these transient strain events ranges from some hours to several days, putting tight constraints on the origin of ground uplifts at Campi Flegrei. Their location is compatible with a source inferred from long term deformation signals, located about 4 km beneath Pozzuoli. A proposed mechanism for these aseismic strain episodes is that they are associated with magma growth in reservoirs with occasional pressure relief associated with the leakage of gas.

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Offshore ground movements in the Campi Flegrei caldera during the last ~12 ka

10.5194/egusphere-egu21-15220 ◽

2021 ◽

Author(s):

Camilla Marino ◽

Luigi Ferranti ◽

Jacopo Natale ◽

Marco Sacchi ◽

Marco Anzidei

Keyword(s):

High Resolution ◽

Ground Deformation ◽

Vertical Displacement ◽

Ground Movement ◽

Campi Flegrei ◽

Caldera Collapse ◽

Deformation Pattern ◽

Central Dome ◽

Ground Movements ◽

Campi Flegrei Caldera

Appraisal of morphodepositional markers tied to ancient sea-levels in high-resolution seismic profiles together with geo-archaeological markers along the coast of the Pozzuoli Bay provided insights into the vertical deformation of the submerged part of the Campi Flegrei caldera (Southern Italy).The collapse of the central part of the Campi Flegrei caldera is associated with the eruption of the Neapolitan Yellow Tuff (NYT) at ~15 ka. The NYT caldera collapse was followed by central dome resurgence associated with alternations of fast uplift and subsidence displacements that accompanied with discrete phases of intra-caldera volcanic activity. Previously, the evolution of ground movement in the Campi Flegrei caldera has been reconstructed using marine deposits uplifted onland or archaeological evidence and historical accounts and thus offers a mainly 2D appraisal of the deformation pattern. However, a complete reconstruction of post-collapse deformation suffers of the limitation that nearly two-thirds of the caldera are submerged beneath the Pozzuoli Bay.We contribute to fill this gap by providing a reconstruction of offshore and coastal deformation through estimation of the vertical displacement of morphodepositional markers in high-resolution seismic reflection profiles and geoarchaeological markers directly surveyed at shallow depths. Our interpretation reveals the occurrence of different sediment stacking pattern whose provides evidence of rapid and oscillating ground movements. Whereas the offshore morphodepositional markers provide displacement information for the last ~12 ka, for the last ~2 ka our interpretation is supported by ancient Roman sea-level indicators. The multi-dataset analysis has allowed disentangling the signal related to the post-caldera dynamics from a broader deformation signal that affects this part of the extensional margin of the Apennines.The integration of offshore data in the study of past episodes of ground deformation, by yielding a more complete picture of the ground motions associated to the post-collapse evolution of the Campi Flegrei caldera, bears a significant contribution for a 3D reconstruction of this high-risk resurgence caldera. Besides, the multidisciplinary approach presented here can be relevant for investigations of other calderas spanning the sea-land transition.

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A new method to assess long‐term sea‐bottom vertical displacement in shallow water using a bottom pressure sensor: Application to Campi Flegrei, Southern Italy

Journal of Geophysical Research Solid Earth ◽

10.1002/2016jb013459 ◽

2016 ◽

Vol 121 (11) ◽

pp. 7775-7789 ◽

Cited By ~ 4

Author(s):

Francesco Chierici ◽

Giovanni Iannaccone ◽

Luca Pignagnoli ◽

Sergio Guardato ◽

Marina Locritani ◽

...

Keyword(s):

Shallow Water ◽

Pressure Sensor ◽

Southern Italy ◽

Vertical Displacement ◽

New Method ◽

Campi Flegrei ◽

Bottom Pressure ◽

Sensor Application ◽

Sea Bottom

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Long-term forecast of eruption style and size at Campi Flegrei caldera (Italy)

Earth and Planetary Science Letters ◽

10.1016/j.epsl.2009.08.013 ◽

2009 ◽

Vol 287 (1-2) ◽

pp. 265-276 ◽

Cited By ~ 76

Author(s):

Giovanni Orsi ◽

Mauro Antonio Di Vito ◽

Jacopo Selva ◽

Warner Marzocchi

Keyword(s):

Campi Flegrei ◽

Eruption Style ◽

Campi Flegrei Caldera ◽

Term Forecast

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High-resolution geological investigations to reconstruct the long-term ground movements in the last 15 kyr at Campi Flegrei caldera (southern Italy)

Journal of Volcanology and Geothermal Research ◽

10.1016/j.jvolgeores.2019.07.012 ◽

2019 ◽

Vol 385 ◽

pp. 143-158 ◽

Cited By ~ 5

Author(s):

Roberto Isaia ◽

Stefano Vitale ◽

Aldo Marturano ◽

Giuseppe Aiello ◽

Diana Barra ◽

...

Keyword(s):

High Resolution ◽

Southern Italy ◽

Campi Flegrei ◽

Ground Movements ◽

Campi Flegrei Caldera

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Tracking Episodes of Seismicity and Gas Transport in Campi Flegrei Caldera Through Seismic, Geophysical, and Geochemical Measurements

Seismological Research Letters ◽

10.1785/0220200223 ◽

2020 ◽

Author(s):

Flora Giudicepietro ◽

Giovanni Chiodini ◽

Rosario Avino ◽

Giuseppe Brandi ◽

Stefano Caliro ◽

...

Keyword(s):

Central Area ◽

Campi Flegrei ◽

Double Difference ◽

High Resistivity ◽

Sudden Increase ◽

Uplift Rate ◽

Gas Emission ◽

Campi Flegrei Caldera ◽

Duration Magnitude ◽

Uplift Rates

Abstract This article presents findings from two episodes of seismicity and gas emission that occurred on 7 October 2015 and 6 December 2019 in Campi Flegrei caldera. This caldera has been affected by long-term unrest since 2004. The 6 December 2019 episode, consisting of a swarm of 38 earthquakes (maximum duration magnitude 3.1, the largest between 1984 and March 2020), occurred at the end of a one month period characterized by an increase in the ground uplift rate from 0.19±0.01 to 0.72±0.05 mm/day. A sudden increase in the fumarolic tremor amplitude, which is a proxy of gas emission-related parameters recorded at Solfatara–Pisciarelli hydrothermal area (e.g., CO2 air concentration), was observed during the seismicity episode. The uplift rate decreased immediately after the swarm (0.10±0.01 mm/day), whereas the fumarolic tremor amplitude remained higher than that observed prior to the swarm. Through analyzing the time series of uplift recorded in Pozzuoli (central area of the caldera) from differential measurements on tide gauges, we were able to identify the 2015 episode. This episode was characterized by increasing uplift rates that culminated in a seismic swarm of 33 earthquakes on 7 October, which was followed by decreasing uplift rates. We computed double-difference locations of earthquakes from the two swarms and found that they located along a conduit-like path, coinciding with a high-resistivity contrast zone, previously identified by audiomagnetotelluric measurements. The focal mechanisms of the major earthquakes of both swarms indicate fault planes radial with respect to the maximum uplift area. These phenomena can be interpreted as episodes of the volcanic and (or) hydrothermal system pressurization that culminate in an injection of fluids along the conduit-like path, which behaves as a valve that allows fluid discharge and the temporary depressurization of the source region.

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Modeling surface deformation observed with synthetic aperture radar interferometry at Campi Flegrei caldera

Journal of Geophysical Research Atmospheres ◽

10.1029/2001jb000194 ◽

2001 ◽

Vol 106 (B9) ◽

pp. 19355-19366 ◽

Cited By ~ 112

Author(s):

P. Lundgren ◽

S. Usai ◽

E. Sansosti ◽

R. Lanari ◽

M. Tesauro ◽

...

Keyword(s):

Synthetic Aperture Radar ◽

Surface Deformation ◽

Radar Interferometry ◽

Synthetic Aperture ◽

Campi Flegrei ◽

Campi Flegrei Caldera ◽

Synthetic Aperture Radar Interferometry ◽

Aperture Radar

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Doming and faulting processes driving ground deformation at Campi Flegrei caldera (southern Italy): a modeling for the last 6 ka

10.5194/egusphere-egu2020-7000 ◽

2020 ◽

Author(s):

Stefano Vitale ◽

Roberto Isaia ◽

Jacopo Natale ◽

Francesco D'Assisi Tramparulo

Keyword(s):

Southern Italy ◽

Ground Deformation ◽

Vertical Displacement ◽

Time Frame ◽

Plinian Eruption ◽

Tectonic Activity ◽

Campi Flegrei ◽

Deformation Pattern ◽

Campi Flegrei Caldera ◽

Caldera Floor

We investigated the major episodes of dome growth in the Campi Flegrei caldera occurred during the last period of large eruptive activity (Epoch 3, between 5.5 and 3.5 ka), and in the historical time. The first doming event occurred at the start of Epoch 3&#160; where the caldera floor raised for at least 100 m. Following the Plinian eruption of Agnano-Monte Spina (AMS, 4.55 ka), a new uplift phase occurred with the set up of several lava domes (e.g., Olibano, Accademia and Solfatara cryptodome), the Averno-Solfatara &#160;(AVS, 4.3 ka) and Astroni (AST, 4.2 ka) eruptions. This unrest episode was accompanied by severe and widespread faulting and fracturing well recorded in the stratigraphic record (Vitale et al., 2019). Finally, the last episodes of doming occurred before the eruption of Monte Nuovo volcano (MN, 1538 CE) and in the last century (1950-1985 CE). The 1538 CE uplift reached a maximum vertical displacement of ca. 15 m, whereas the 1950-1985 events reached a total dislocation of ca. 4 m. In order to study the former ground deformation pattern, we reconstructed the top surface of the La Starza succession, the latter formed by marine-transitional sediments deposited between 15 and 5.5 ka deposited in large part of the caldera floor. We used information from onland well-logs and seismic profiles in the Gulf of Pozzuoli. The same approach was used for the top surface of the younger marine succession, called Pozzuoli Unit (PU) (Isaia et al., 2019), emplaced following the AMS eruption and predating the AVS eruption. Subtracting the historical deformation pattern and considering the sea-level change in that time frame, we observe that the center of vertical deformation was located, for both Top Starza and Top PU surfaces, close to the Cigliano vent, and therefore not coinciding with the 1538 CE and recent deformation center, both defined by the same deformation center located close to the town of Pozzuoli. The resulting surfaces well mark local deformations related to the activity of major faults and the minor caldera formed following the AMS Plinian eruption. The restoring of the deformation of major faults with the Okada&#8217;s fault model has furnished useful information about the amount of displacement and rates of the faults' activity in the last ca. 6 ka.Isaia, R., Vitale, S., Marturano, A., Aiello, G., Barra, D., Ciarcia, S., Iannuzzi, E., Tramparulo, F.D.A., 2019. High-resolution geological investigations to reconstruct the long-term ground movements in the last 15 kyr at Campi Flegrei caldera (southern Italy). Journal of Volcanology and Geothermal Research, 385, 143-158. doi: 10.1016/j.jvolgeores.2019.07.012Vitale, S., Isaia, R., Ciarcia, S., Di Giuseppe, M. G., Iannuzzi, E., Prinzi, E. P., Tramparulo, F.D&#8217;A., Troiano, A. 2019. Seismically induced soft&#8208;sediment deformation phenomena during the volcano&#8208;tectonic activity of Campi Flegrei caldera (southern Italy) in the last 15 kyr.&#160;Tectonics,&#160;38(6), 1999-2018.

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