Drilling and logging results of USDP-4 — Penetration into the volcanic conduit of Unzen Volcano, Japan

Sakuma, Sumio; Kajiwara, Toshinori; Nakada, Setsuya; Uto, Kozo; Shimizu, Hiroshi

doi:10.1016/j.jvolgeores.2008.03.039

Cited by 38 publications

(39 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Numerical simulation tests demonstrate that model seismicity data show power law scaling for internal friction angles > c. 35 degrees. Drilling at Unzen volcano, Japan 40 , where borehole washout and accidental side tracking occurred to several hundred metres depth, testifies to the unconsolidated nature of subsurface volcanic materials at depth -demonstrating that the physical properties determined by Apuani et al 33 and used in our simulations are not merely superficial. Consistent with our numerical seismicity results (Fig.…”

Section: Volcano Seismicity and Other 'Slow-rupture' Observationssupporting

confidence: 51%

Long-period seismicity in the shallow volcanic edifice formed from slow-rupture earthquakes

et al. 2013

View full text Add to dashboard Cite

Section: Volcano Seismicity and Other 'Slow-rupture' Observationssupporting

confidence: 51%

Long-period seismicity in the shallow volcanic edifice formed from slow-rupture earthquakes

et al. 2013

View full text Add to dashboard Cite

“…The critical stress state at this transition, known as C * , has been previously described in sedimentary materials (e.g. Schock et al, 1973;Baud et al, 2000;Vajdova et al, 2004;Baud et al, 2006;Regnet et al, 2015) and recently in andesite from Volcán de Colima (Heap et al, 2015a). As anticipated, beyond a threshold stress-strain accumulation, sample LLB-13 exhibits a transition from compactant deformation to dilatant behaviour (highlighted by the arrow in Fig.…”

Section: A Limit To Compaction and Permeability Reductionsupporting

confidence: 64%

“…Bulk rock density and porosity have been estimated during scientific drilling projects -in concert with gravimetric and other geophysical data -at, for example, Campi Flegrei, Italy (Barberi et al, 1991), and Mount Unzen (Sakuma et al, 2008). These studies highlight a predictable decrease in porosity with increasing depth, supported in either case by a general increase in ultrasonic wave velocities with increasing depth, indicative of a reduction in porosity with increasing lithostatic pressure.…”

Section: Introductionmentioning

confidence: 99%

Inelastic compaction and permeability evolution in volcanic rock

2017

View full text Add to dashboard Cite

Abstract. Active volcanoes are mechanically dynamic environments, and edifice-forming material may often be subjected to significant amounts of stress and strain. It is understood that porous volcanic rock can compact inelastically under a wide range of in situ conditions. In this contribution, we explore the evolution of porosity and permeability -critical properties influencing the style and magnitude of volcanic activity -as a function of inelastic compaction of porous andesite under triaxial conditions. Progressive axial strain accumulation is associated with progressive porosity loss. The efficiency of compaction was found to be related to the effective confining pressure under which deformation occurred: at higher effective pressure, more porosity was lost for any given amount of axial strain. Permeability evolution is more complex, with small amounts of stress-induced compaction ( < 0.05, i.e. less than 5 % reduction in sample length) yielding an increase in permeability under all effective pressures tested, occasionally by almost 1 order of magnitude. This phenomenon is considered here to be the result of improved connectivity of formerly isolated porosity during triaxial loading. This effect is then overshadowed by a decrease in permeability with further inelastic strain accumulation, especially notable at high axial strains (> 0.20) where samples may undergo a reduction in permeability by 2 orders of magnitude relative to their initial values. A physical limit to compaction is discussed, which we suggest is echoed in a limit to the potential for permeability reduction in compacting volcanic rock. Compiled literature data illustrate that at high axial strain (both in the brittle and ductile regimes), porosity φ and permeability k tend to converge towards intermediate values (i.e. 0.10 ≤ φ ≤ 0.20; 10 −14 ≤ k ≤10 −13 m 2 ). These results are discussed in light of their potential ramifications for impacting edifice outgassing -and in turn, eruptive activity -in active volcanoes.

show abstract

“…However, dikes may often become arrested of the composition of magma. The shallow conduit of volcanoes may be imaged as a cluster of dikes, as confirmed by recent drilling in the conduit zone of Unzen volcano, consisting of a hundreds of m wide dike zone (Sakuma et al, 2008). Dikes may reach lengths of tens of km, delivering magma and feeding eruptions for significant distances also outside volcanoes.…”

Section: Challenge 2: Propagation and Arrest Of Magmamentioning

confidence: 82%

Great challenges in volcanology: how does the volcano factory work?

Acocella

2014

Front. Earth Sci.

View full text Add to dashboard Cite

Drilling and logging results of USDP-4 — Penetration into the volcanic conduit of Unzen Volcano, Japan

Cited by 38 publications

References 13 publications

Long-period seismicity in the shallow volcanic edifice formed from slow-rupture earthquakes

Long-period seismicity in the shallow volcanic edifice formed from slow-rupture earthquakes

Inelastic compaction and permeability evolution in volcanic rock

Great challenges in volcanology: how does the volcano factory work?

Contact Info

Product

Resources

About