Changes in seismicity with time and location are diagnostic signals for understanding the dynamics of volcanic unrest. We used these at Campi Flegrei caldera, southern Italy, to investigate how structural changes have determined three styles unrest since 1982, distinguished by a ground uplift (measured Pozzuoli, near centre caldera) 178 cm 1982–84; subsidence 93 1985–2005; an 118 between 2005 November 2023. Double-difference seismic locations concentrations energy release revealed...

Breakout of magmatic activity at Soufriere Hills volcano, Montserrat, was preceded by a tenfold increase in rate earthquake occurrence. A new model subcritical rock failure shows that this is consistent with the growth, possibly episodic, magma conduit controlled progressive weakening host country rock. The preferred mechanism stress corrosion, which circulating juvenile and hydrothermal fluids chemically attack promote stresses smaller than rock's theoretical strength. results illuminate...

Unrest at large calderas rarely ends in eruption, encouraging vulnerable communities to perceive emergency warnings of volcanic activity as false alarms. A classic example is the Campi Flegrei caldera southern Italy, where three episodes major uplift since 1950 have raised its central district by about 3 m without an eruption. Individual conventionally been treated independent events, so that only data from ongoing episode are considered pertinent evaluating eruptive potential. An implicit...

Abstract The late Pre‐Cambrian Portaskaig Boulder Bed Series shows a very uniform sequence for some 600 km along the Caledonian strike, from Connemara on west coast of Ireland to Aberdeenshire in Scotland. Series, which is divided into four groups beds, comprises numerous individual boulder beds separated by stratified sediments. lower are carbonate‐bearing and contain abundant intrabasinal fragments dolomite few extrabasinal crystalline rocks while higher psammitic mainly rocks. Varve‐like...

Abstract Volcanoes reawakening after long repose must rupture the crust before magma can erupt. Rupture is preceded by repeatable variations in rate of seismicity with ground movement, which trace amount applied stress that released local earthquakes. A rupturing sequence has been developing across four episodes uplift at Italy’s Campi Flegrei caldera: 1950-1952, 1969-1972, 1982-1984 and since 2004. We predicted 2016 approach to would continue an additional 30-40 cm location largest...

Lava flow fields consist of one or more flows. Four ideal emplacement regimes are recognized: (a) that for single flows and (b) dominated by (1) widening, (2) thickening, (3) lengthening, as a result generating new Most aa blocky lavas belong to the field widening single‐flow regimes. These two analyzed assuming advance is controlled distal core flow, where motion treated steady, uniform, laminar. Because low deformation rates, also approximated Newtonian fluid. Widening and, possibly,...

Small‐magnitude earthquakes and ground deformation are the precursors most frequently recorded before volcanic eruptions. Analogous signals (using acoustic emissions) have also been reported bulk brittle failure of crustal rock in laboratory. Models based on laboratory field data focused precursory behavior during under a constant stress. A new model is proposed for extending analyses to an increasing It describes how time series can be determined from parent relation between fracturing...

The Campi Flegrei volcanic district, in southern Italy, has been uplifted since 1968 by a net maximum of 3 m during the intervals 1968–1972 and 1982–1984. uplift represents permanent deformation against background rate subsidence about 17 mm −1 . Previous models have reproduced observed vertical but not full pattern horizontal movements. 1982–1983 is here reanalyzed terms penny‐shaped sill on its own, with tabular surface protrusion, or an extensional stress field. It can be explained best...

The historical lavas on Mount Etna provide a large body of data for examining the growth aa flow fields. A field, final product an eruption, is composed one or more flows. Flow generation depends ratio S R /S D crustal retaining strength (S ) to stress driving lava outward ), rate thickening h , and time which sustained. At low advances by simple spreading, new flows are formed subdividing about topographic highs (bifurcation). h, growing crusts can contain at all values . Overflow chilled...

Abstract Campi Flegrei caldera, west of Naples in southern Italy, has an exceptional documented record ground deformation from Roman times onwards. Systematic recording began the nineteenth century. For earlier dates, information been obtained archaeological studies and contemporary descriptions locations buildings, usually Roman, with respect to sea-level. Especially important have accounts related Serapis, a market-place built second century bc now incorporated within modern town Pozzuoli....

Volcano-tectonic seismicity and ground movement are the most reliable precursors to eruptions after extended intervals of repose, as well flank from frequently-active volcanoes. Their behavior is consistent with elastic-brittle failure crust before a new pathway opened allow magma ascent. A modified physical model shows that precursory time series governed by parent relation between faulting elastic deformation in extension, subject independent constraints on rate crustal loading time. The...

  Rapid, giant landslides, or sturzstroms, are among the most powerful natural hazards on Earth. They produced by catastrophic, deep-seated slope collapses with minimum volumes order of 10⁶–10⁷ m³. Such often final stage accelerating movement that may have continued for years. Measurements made over 60 years ago before failure Mt. Toc into Vajont reservoir in Italian Alps remain one best records pre-collapse movement. Numerous studies...

Sturzstroms are giant landslides that travel kilometers within minutes. Data from terrestrial examples of 0.001–10 km 3 suggest their runout lengths increase in proportion to the square root volume. This trend is investigated assuming controlled by fragmental flow. The results indicate depend on potential energy available for motion after initial collapse (itself a function dimensions zone), degree rock fragmentation, and rate momentum loss fragment collisions basal boundary layer, assumed...