Elastostatic effects around a magma reservoir and pathway due to historic earthquakes: a case study of Mt. Fuji, Japan
© The Author(s). 2016
Received: 4 May 2016
Accepted: 13 October 2016
Published: 24 October 2016
We discuss elastostatic effects on Mt. Fuji, the tallest volcano in Japan, due to historic earthquakes in Japan. The 1707 Hoei eruption, which was the most explosive historic eruption of Mt. Fuji, occurred 49 days after the Hoei earthquake (Mw 8.7) along the Nankai Trough. It was previously suggested that the Hoei earthquake induced compression of a basaltic magma reservoir and unclamping of a dike-intruded region at depth, possibly triggering magma mixing and the subsequent Plinian eruption. Here, we show that the 1707 Hoei earthquake was a special case of induced volumetric strain and normal stress changes around the magma reservoir and pathway of Mt. Fuji. The 2011 Tohoku earthquake (Mw 9), along the Japan Trench, dilated the magma reservoir. It has been proposed that dilation of a magma reservoir drives the ascent of gas bubbles with magma and further depressurization, leading to a volcanic eruption. In fact, seismicity notably increased around Mt. Fuji during the first month after the 2011 Tohoku earthquake, even when we statistically exclude aftershocks, but the small amount of strain change (< 1 μ strain) may have limited the ascent of magma. For many historic earthquakes, the magma reservoir was compressed and the magma pathway was wholly clamped. This type of interaction has little potential to mechanically trigger the deformation of a volcano. Thus, Mt. Fuji may be less susceptible to elastostatic effects because of its location relative to the sources of large tectonic earthquakes. As an exception, a possible local earthquake in the Fujikawa-kako fault zone could induce a large amount of magma reservoir dilation beneath the southern flank of Mt. Fuji.
KeywordsVolcano–earthquake interactions Elastostatic deformation Epidemic-type aftershock sequence model Boundary-element method simulation Dike Magma pathway Magma reservoir Mt. Fuji 2011 Tohoku earthquake 1707 Hoei earthquake
Volcano–earthquake interactions have been discussed mainly from a statistical perspective. A previous study (Linde and Sacks 1998) found that the frequency of volcanic eruptions tended to increase within 1 or 2 days after nearby large earthquakes. Another study (Lemarchand and Grasso 2007) showed that volcanic eruptions also increased before earthquakes and proposed a conceptual model of regional tectonic coupling between volcanoes and earthquakes. Such reports are scientifically interesting; thus, we approach this issue in terms of mechanical effects. In particular, we focus on the tallest volcano in Japan, Mt. Fuji (3776 m).
One of the largest eruptions of Mt. Fuji, the VEI 5 Hoei eruption, occurred in 1707 as a lateral eruption in a region of northwest–southeast striking dikes. At 49 days before the eruption, a large interplate earthquake (Mw 8.7) occurred at the interface between the Eurasian Plate and the Philippine Sea Plate. A previous study (Nakamura 1975) discussed this issue and proposed that the large earthquake reduced the minimum principal stress in the region, leading to the lateral eruption.
Here, we note that the main dike region of Mt. Fuji was not the only path of ascending magma near the surface. For example, a geological study (Takada et al. 2007) investigated eruptive fissure patterns at Mt. Fuji and showed a spatially asymmetric distribution (Fig. 2). Eruptive fissures are concentrated mainly in the direction of the dike plane (aligned northwest–southeast) but are also distributed in other directions. This observation implies that local stress heterogeneities other than the collision-induced regional stress field (Ukawa 1991) can play an important role in constraining the locations of eruptive fissures. Araragi et al. (2015) investigated the anisotropic structure beneath Mt. Fuji by shear wave splitting and found a radial pattern of fast polarization directions toward the summit at depths shallower than 4 km, which reflects gravitational stress effects due to mountain loads. In addition, (magmatic) deep low-frequency earthquakes have occurred on the northeast side of the volcanic edifice (Nakamichi et al. 2004), seemingly located off the dike plane. An increase in seismicity after the 2011 Tohoku earthquake (Enescu et al. 2012) occurred along a different direction from that of the dike plane.
In this study, we evaluate the elastostatic effects beneath Mt. Fuji due to large (Mw 8 or Mw 9 class) earthquakes in Japan. First, we calculate the volumetric strain changes around the magma reservoir and the dike plane, and the normal stress changes perpendicular to the dike plane, using several scenarios modeled using historic earthquakes near Mt. Fuji, to compare with two existing hypotheses for eruption-triggering processes due to earthquakes. Next, we calculate the elastostatic effects for another direction (nearly north–south) along a weak zone as a representative example of a possible magma ascent path and discuss the response of the volcano system in terms of compression/dilation of the magma reservoir and clamping/unclamping of the magma pathway.
Elastostatic modeling of earthquake deformation
Fault parameters used in this study. The parameters for (a) and (b) follow Chesley et al. (2012). Those for (c) are from a geodetic study (Nishimura et al. 2011) including the largest aftershock. We set the parameters for (d) on the basis of underground and surface fault geometry (Sato et al. 2004; Panayotopoulos et al. 2014). The parameters for (e) are from Ishibashi (1977)
Long.a [° E]
Lati.a [° N]
Results and discussion
Elastostatic modeling of earthquake deformation
We first calculate the spatial distribution of the volumetric strain changes (the sum of the normal components of the tensor). The volumetric strain change around the magma reservoir may relate to an increasing magma overpressure effect (Walter and Amelung 2007) as a source of eruption. Although the spatial distribution of the magma reservoir beneath Mt. Fuji remains unclear, a seismic tomography study (Nakamichi et al. 2007) revealed a high-Vp/Vs anomaly around 15–25 km depth that is interpreted as a zone of basaltic partial melting. Another study (Kinoshita et al. 2015) used receiver function analysis to show a seismic velocity contrast at 20–30 km depth, which can be related to the bottom of the magma chamber. In addition, over 90 % of (magmatic) low-frequency earthquakes in Fig. 2 occurred in a depth range of 10–20 km. Thus, we focus on the strain changes at a depth of 20 km, treating this as a typical value for the depth of a basaltic magma reservoir beneath Mt Fuji.
Two hypotheses that explain eruption triggering by elastostatic deformation
We estimated two kinds of elastostatic effects: volumetric strain changes around the basaltic magma reservoir and normal stress changes perpendicular to the extended dike plane (the main pathway of Mt. Fuji’s magma). Because we do not consider material contrasts surrounding the magma reservoir, as in Fujita et al. (2013), the calculated values represent the mean fields of peripheral domains. The magnitudes of the elastostatic effects, around 1 MPa at most, are not negligible beneath Mt. Fuji because the differential stress there may be relatively small. For instance, Araragi et al. (2015) proposed that the maximum horizontal stress is only 1.02× greater than lithostatic pressure. They raised an example of a lithostatic pressure of 51.9 MPa at a depth of 2.0 km, which means the difference between the maximum horizontal stress and the lithostatic pressure would be about 1 MPa at that depth.
A previous study of volcano–earthquake interactions (Walter and Amelung 2007) proposed that dilation of a magma reservoir initiates magma ascent, on the basis of volcano eruption data after M ≥9 megathrust earthquakes worldwide. That is, earthquake-induced dilation (depressurization) released dissolved volatile gases (CO2 and H2O), leading to volumetric expansion of a magma reservoir. This process decreases the density and viscosity of the magma, though the latter is perhaps not necessarily as suggested by Bottinga and Weill (1972) and Urbain et al. (1982). This, in turn, drives the ascent of gas bubbles with magma, causing further depressurization. In one possible scenario, this leads to an eruption through a positive feedback loop (Walter and Amelung 2007). Since the process of bubble nucleation under sudden depressurization depends on many factors (e.g., Toramaru 2014), the threshold level and conditions for the beginning of this magma ascent process remain unclear.
From this viewpoint and Fig. 5, only two earthquakes, the Tohoku earthquake (c) and the ISTL earthquake (d), have the potential to have initiated volcanic activity. At present, we know that the 2011 Tohoku earthquake has not yet triggered an eruption at Mt. Fuji. The reason for this is probably that the amount of magma dilation was small (< 1 μ strain) relative to known cases of volcanic eruptions after M ≥9 megathrust earthquakes (Walter and Amelung 2007) or that the magma state was not favorable to drive the ascent for eruption (Fujita et al. 2013). Although the 2011 Tohoku earthquake did not trigger an eruption at Mt. Fuji, one point to be noted is that many earthquakes, including a Mw 5.9 earthquake near Mt. Fuji, followed the 2011 Tohoku earthquake (Enescu et al. 2012; Kumazawa and Ogata 2013). We will statistically analyze these induced earthquakes in a later section. The ISTL earthquake, which occurred in 762 or 841, also did not trigger an eruption at Mt. Fuji; similarly, this is thought to be due to the small amount of magma dilation.
In contrast, Nostro et al. (1998) proposed another hypothesis linking volcanic eruptions with earthquakes at Mt. Vesuvius. They suggested that compression of a magma reservoir and unclamping of a dike (magma pathway) by earthquakes led to eruptions. From Figs. 5 and 6, we found no cases corresponding to this model for Mt. Fuji, but the Hoei earthquake (a) was the closest analog. The 1707 Hoei earthquake compressed the basaltic magma reservoir and partly unclamped the main dike, especially in deeper regions, which might have uplifted sufficient basaltic magma to trigger magma mixing and the Plinian eruption 49 days after the Hoei earthquake (Chesley et al. 2012). The case of the 1854 Tokai earthquake (e) is a similar situation, but unclamping in the deep region of the main dike is almost negligible. This might explain why the 1854 Tokai earthquake did not trigger an eruption at Mt. Fuji. In addition, a recharge time of only ~150 years might be too short, particularly for another Plinian eruption. It is possible that the 1703 Kanto earthquake (b) did not lead to an eruption of Mt. Fuji because of total clamping of the extended dike plane, which tends to suppress magma ascent.
In addition, the effects of dynamic stress changes, which we do not examine in this study, may promote eruption triggering (Manga and Brodsky 2006). We acknowledge that elastodynamic effects alone could explain eruptions following distant large earthquakes many hundreds of kilometers away, but there is no evidence of elastodynamic effects exceeding the elastostatic effects due to nearby earthquakes. As an example, Ichihara and Brodsky (2006) revealed that rectified diffusion, one of the popular physical mechanisms of elastodynamic effects, causes pressure changes of at most 2 × 10− 9 of initial values for seismic waves with typical amplitudes. If this is true, then elastodynamic effects due to rectified diffusion are negligible compared with the elastostatic effects reported in this study. Moreover, it seems difficult to explain the rarity of the 1707 Hoei case in terms of elastodynamic effects compared with elastostatic effects. In Fig. 11 and below, we further discuss volcano responses to earthquake deformation.
Statistical analysis of seismicity after the 2011 Tohoku earthquake
Whether or not post-Tohoku seismicity reflects magma movement at depth is scientifically interesting. Here, we statistically analyze seismicity in 2011 for the region shown in Fig. 7 using the ETAS (epidemic-type aftershock sequence) model (Ogata 1988). Adopting an ETAS model allows us to evaluate the background seismicity rate μ without the effects of aftershocks. A seismological study by Llenos et al. (2009) proposed that changes in μ reflect alterations to aseismic stressing rates around earthquake hypocenters. We now apply this concept to seismicity around Mt. Fuji.
To estimate the model parameters, we use SASeis2006 (Ogata 2006), which estimates the five ETAS parameters (μ, K, c, α, p) by minimizing the value of the Akaike Information Criterion (Akaike 1974) with a fast likelihood algorithm (Ogata et al. 1993). For the actual parameter estimation, we set M c = 1.0 to remove small earthquakes from calculation of the Gutenberg–Richter law (Gutenberg and Richter 1944) for seismic data in this region. We also assume initial parameter values for the estimation algorithm of (μ, K, c, α, p) = (1, 1, 0.5, 1, 1.5).
Why earthquakes now occur along the PPP instead of the (extended) dike plane is an ongoing mystery. Recent geophysical observations have found no evidence for volcanic activity along the (extended) dike plane. One possible hypothesis is that the main pathway of the magma changed from the (extended) dike plane following the 1707 Hoei eruption. Since the 1707 Hoei eruption was the most explosive historic eruption of Mt. Fuji, it might have changed the internal structure and stress state around the volcanic edifice. Another hypothesis is that the path of magma ascent fluctuates on relatively short time scales, and the present pathway is not along the (extended) dike plane. This hypothesis may be supported by the star-like shape of the fissure distribution (e.g., Fig. 2), but what causes the fluctuations is truly unknown. If such fluctuations are controlled by the thermal diffusion system, then their time scales would be far longer than those discussed in this study.
Implications for volcano response following earthquake-induced deformation
In many other cases, the magma reservoir was compressed and the dike was wholly clamped (lower left quadrant in Fig. 11). It seems that the volcanic system was not activated in these cases. This is because the compression of the magma reservoir itself would not be enough to trigger an eruption, as discussed in the previous sections. If other large earthquakes compressed the magma reservoir and unclamped the dike beneath Mt. Fuji, the volcano system might respond acutely, as discussed previously (Nostro et al. 1998). Likewise, if another large tectonic earthquake dilated the magma reservoir by an order of magnitude more than the 2011 Tohoku earthquake and the ISTL earthquake, then the volcano system might possibly respond as proposed in a previous study (Walter and Amelung 2007). However, we cannot identify a tectonic earthquake large enough to produce such dilation. This fact implies that the magmatic system beneath Mt. Fuji is almost insulated from the elastostatic influences of large tectonic earthquakes.
Effects of other possible local events near Mt. Fuji
Around the northern parts of the magma pathways (both the extended dike plane and PPP), the magma reservoir is compressed and the pathways are clamped, similar to the effects of the 1703 Kanto earthquake on the extended dike plane. As discussed in the previous section, this does not favor eruption triggering. In contrast, the calculation results for the southern parts of the magma pathways (both the extended dike plane and PPP) are qualitatively similar to the case of the Tohoku earthquake. Namely, the magma reservoir is dilated while the extended dike plane is unclamped and the PPP is clamped. We note that the values of the elastostatic effects are somewhat larger than the case of the 2011 Tohoku earthquake. This local FKFZ earthquake may have the power to trigger an eruption around the southern parts of the magma pathways, following the model of Walter and Amelung (2007).
Another possible seismic event that could affect Mt. Fuji is one or more M7 slow slip events downdip of the source fault of the Tokai earthquake (Ozawa et al. 2016). Since the location of the slow slip events is near the Tokai earthquake, the effects would be qualitatively similar to, but orders of magnitude smaller than, the Tokai earthquake (case (e) in the previous sections).
We estimated the elastostatic effects caused by large historic and recent earthquakes in Japan around the magma reservoir of Mt. Fuji, including two possible magma pathways: a northwest–southeast-trending extended dike plane and a north–south aligned possible pathway plane. The 2011 Tohoku earthquake induced dilation of the magma reservoir, but the small amount (< 1 μ strain) would limit the potential for triggering eruption (Walter and Amelung 2007). The 1707 Hoei eruption (the most explosive historic eruption at Mt. Fuji), which followed the Hoei earthquake by 49 days, may be a special case that is consistent with the model of Nostro et al. (1998), i.e., triggering due to magma ascent in the deep region of the dike plane (Chesley et al. 2012). Many earthquake scenarios are characterized by compression of the magma reservoir and clamping of the magma pathway, which is far from the conditions proposed by Walter and Amelung (2007) and Nostro et al. (1998) for eruptions triggered by earthquakes. Given its location relative to mature faults in Japan, Mt. Fuji may be less susceptible to the elastostatic effects of tectonic large earthquakes. We also showed that a possible local earthquake in the Fujikawa-kako fault zone can cause far greater dilation of the magma reservoir than the 2011 Tohoku earthquake beneath the southern flank of Mt. Fuji.
We used the Generic Mapping Tools software package (Wessel and Smith 1995) to draw the maps in Figs. 1, 2, 3, 4, 5, 6, 7, 10, and 12. We thank two anonymous reviewers for comments that substantially improved the manuscript.
MH proposed the initial idea and performed the elastostatic simulations. YM discussed the results and wrote the paper. HI discussed the results. JK performed the statistical analysis. All authors read and approved the final manuscript.
The authors declare that they have no competing interests.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
- Akaike H (1974) A new look at the statistical model identification. IEEE Trans Autom Contr 19:716–723. doi:10.1109/TAC.1974.1100705 View ArticleGoogle Scholar
- Ando M (1975) Source mechanisms and tectonic significance of historical earthquakes along the Nankai Trough, Japan. Tectonophysics 27:119–140. doi:10.1016/0040-1951(75)90102-X View ArticleGoogle Scholar
- Araragi KR, Savage MK, Ohminato T, Aoki Y (2015) Seismic anisotropy of the upper crust around Mount Fuji, Japan. J Geophys Res 120:2739–2751. doi:10.1002/2014JB011554 View ArticleGoogle Scholar
- Bonali FL, Tibaldi A, Corazzato C et al (2013) Quantifying the effect of large earthquakes in promoting eruptions due to stress changes on magma pathway: the Chile case. Tectonophysics 583:54–67. doi:10.1016/j.tecto.2012.10.025 View ArticleGoogle Scholar
- Bottinga Y, Weill DF (1972) The viscosity of magmatic silicate liquids; a model calculation. American J Sci 272:438–475. doi:10.2475/ajs.272.5.438 View ArticleGoogle Scholar
- Chesley C, LaFemina PC, Puskas C, Kobayashi D (2012) The 1707 Mw 8.7 Hoei earthquake triggered the largest historical eruption of Mt. Fuji. Geophys Res Lett 39:L24309. doi:10.1029/2012GL053868 View ArticleGoogle Scholar
- Dieterich J (1994) A constitutive law for rate of earthquake production and its application to earthquake clustering. J Geophys Res 99:2601–2618. doi:10.1029/93JB02581 View ArticleGoogle Scholar
- Eichelberger JC (1980) Vesiculation of mafic magma during replenishment of silicic magma reservoirs. Nature 288:446–450. doi:10.1038/288446a0 View ArticleGoogle Scholar
- Enescu B, Aoi S, Toda S et al (2012) Stress perturbations and seismic response associated with the 2011 M9.0 Tohoku-oki earthquake in and around the Tokai seismic gap, central Japan. Geophys Res Lett 39:L00G28. doi:10.1029/2012GL051839 View ArticleGoogle Scholar
- Fujita E, Kozono T, Ueda H et al (2013) Stress field change around the Mount Fuji volcano magma system caused by the Tohoku megathrust earthquake, Japan. Bull Vol 75:1–14. doi:10.1007/s00445-012-0679-9 Google Scholar
- Gudmundsson A (2007) Infrastructure and evolution of ocean-ridge discontinuities in Iceland. J Geodynamics Vol 43:6–29. doi:10.1016/j.jog.2006.09.002 View ArticleGoogle Scholar
- Gutenberg B, Richter CF (1944) Frequency of earthquakes in California. Bull Seis Soc Am 34:185–188Google Scholar
- Himematsu Y, Furuya M (2015) Aseismic strike–slip associated with the 2007 dike intrusion episode in Tanzania. Tectonophysics 656:52–60. doi:10.1016/j.tecto.2015.06.005 View ArticleGoogle Scholar
- Ichihara M, Brodsky E (2006) A limit on the effect of rectified diffusion in volcanic systems. Geophys Res Lett 33:L02316. doi:10.1029/2005GL024753 View ArticleGoogle Scholar
- Ida Y (2009) Dependence of volcanic systems on tectonic stress conditions as revealed by features of volcanoes near Izu peninsula, Japan. J Vol Geotherm Res 181:35–46. doi:10.1016/j.jvolgeores.2008.12.006 View ArticleGoogle Scholar
- Ishibashi K (2004) Status of historical seismology in Japan. Ann Geophys 47:339–368Google Scholar
- Ishibashi K (1977) Re-examination of a great earthquake expected in the Tokai district, central Japan—possibility of the “Suruga Bay earthquake”. Rep Coord Comm Earthq Predict 17:126–132Google Scholar
- Kinoshita SM, Igarashi T, Aoki Y, Takeo M (2015) Imaging crust and upper mantle beneath Mount Fuji, Japan, by receiver functions. J Geophys Res 120:3240–3254. doi:10.1002/2014JB011522 View ArticleGoogle Scholar
- Kondo H, Toda S, Okumura K et al (2008) A fault scarp in an urban area identified by LiDAR survey: a case study on the Itoigawa–Shizuoka Tectonic Line, central Japan. Geomorphology 101:731–739. doi:10.1016/j.geomorph.2008.02.012 View ArticleGoogle Scholar
- Koyama M (1998) Reevaluation of the eruptive history of Fuji Volcano, Japan, mainly based on historical documents (in Japanese with English abstract). Bull Volcanol Soc Jpn 43:323–347Google Scholar
- Kumazawa T, Ogata Y (2013) Quantitative description of induced seismic activity before and after the 2011 Tohoku-Oki earthquake by nonstationary ETAS models. J Geophys Res 118:1–18. doi:10.1002/2013JB010259 View ArticleGoogle Scholar
- Lemarchand N, Grasso J-R (2007) Interactions between earthquakes and volcano activity. Geophys Res Lett 34:L24303. doi:10.1029/2007GL031438 View ArticleGoogle Scholar
- Lin A, Iida K, Tanaka H (2013) On-land active thrust faults of the Nankai-Suruga subduction zone: the Fujikawa-kako Fault Zone, central Japan. Tectonophysics 601:1–19. doi:10.1016/j.tecto.2013.04.020 View ArticleGoogle Scholar
- Linde AT, Sacks IS (1998) Triggering of volcanic eruptions. Nature 395:888–890. doi:10.1038/27650 View ArticleGoogle Scholar
- Llenos AL, McGuire JJ, Ogata Y (2009) Modeling seismic swarms triggered by aseismic transients. Earth Planet Sci Lett 281:59–69. doi:10.1016/j.epsl.2009.02.011 View ArticleGoogle Scholar
- Manga M, Brodsky E (2006) Seismic triggering of eruptions in the far field: volcanoes and geysers. Ann Rev Earth Planet Sci 34:263–291. doi:10.1146/annurev.earth.34.031405.125125 View ArticleGoogle Scholar
- McNutt SR, Nishimura T (2008) Volcanic tremor during eruptions: temporal characteristics, scaling and constraints on conduit size and processes. J Vol Geotherm Res 178:10–18View ArticleGoogle Scholar
- Miyaji N (1988) History of younger Fuji Volcano (in Japanese with English abstract). J Geol Soc Japan 94:433–452View ArticleGoogle Scholar
- Nakamichi H, Ukawa M, Sakai S (2004) Precise hypocenter locations of midcrustal low-frequency earthquakes beneath Mt. Fuji, Japan. Earth Planets Sp 56:e37–e40. doi:10.1186/BF03352542 View ArticleGoogle Scholar
- Nakamichi H, Watanabe H, Ohminato T (2007) Three-dimensional velocity structures of Mount Fuji and the South Fossa Magna, central Japan. J Geophys Res. doi: 10.1029/2005JB004161
- Nakamura K (1977) Volcanoes as possible indicators of tectonic stress orientation—principle and proposal. J Vol Geotherm Res 2:1–16. doi:10.1016/0377-0273(77)90012-9 View ArticleGoogle Scholar
- Nakamura K (1975) Volcano structure and possible mechanical correlation between volcanic eruptions and earthquakes (in Japanese with English abstract). Bull Volcanol Soc Jpn 20:229–240Google Scholar
- Nakamura K (1971) Volcano as a possible indicator of crustal strain (in Japanese with English abstract). Bull Volcanol Soc Jpn 16:63–71Google Scholar
- Nishimura T, Munekane H, Yarai H (2011) The 2011 off the Pacific coast of Tohoku Earthquake and its aftershocks observed by GEONET. Earth Planets Sp 63:631–636. doi:10.5047/eps.2011.06.025 View ArticleGoogle Scholar
- Nostro C, Stein RS, Cocco M et al (1998) Two-way coupling between Vesuvius eruptions and southern Apennine earthquakes, Italy, by elastic stress transfer. J Geophys Res 103:24487–24504. doi:10.1029/98JB00902 View ArticleGoogle Scholar
- Ogata Y (1988) Statistical models for earthquake occurrences and residual analysis for point processes. J Am Stat Assoc 83:9–27View ArticleGoogle Scholar
- Ogata Y (2006) Statistical analysis of seismicity: updated version (SASeis 2006). In: Computer science monographs: a publication of the Institute of Statistical Mathematics; No. 33. The Institute of Statistical Mathematics, pp 1–28
- Ogata Y, Matsu’ura RS, Katsura K (1993) Fast likelihood computation of epidemic type aftershock‐sequence model. Geophys Res Lett 20:2143–2146. doi:10.1029/93GL02142 View ArticleGoogle Scholar
- Okada Y (1992) Internal deformation due to shear and tensile faults in a half-space. Bull Seis Soc Am 82:1018–1040Google Scholar
- Okumura K (2001) Paleoseismology of the Itoigawa-Shizuoka tectonic line in central Japan. J Seismol 5:411–431. doi:10.1023/A:1011483811145 View ArticleGoogle Scholar
- Omori F (1894) On the aftershocks of earthquakes. J Coll Sci Imp Univ Tokyo 7:111–120Google Scholar
- Ozawa S, Tobita M, Yarai H (2016) A possible restart of an interplate slow slip adjacent to the Tokai seismic gap in Japan. Earth Planets Space 68:54. doi:10.1186/s40623-016-0430-4 View ArticleGoogle Scholar
- Panayotopoulos Y, Hirata N, Sato H et al (2014) Investigating the role of the Itoigawa-Shizuoka tectonic line towards the evolution of the Northern Fossa Magna rift basin. Tectonophysics 615–616:12–26. doi:10.1016/j.tecto.2013.12.014 View ArticleGoogle Scholar
- Pollard DD, Segall P (1987) Theoretical displacements and stresses near fractures in rock: with applications to faults, joints, veins, dikes, and solution surfaces. In: Fracture Mechanics of Rock. pp 277–349
- Rikitake T, Sato R (1989) Up-squeezing of magma under tectonic stress. J Phys Earth 37:303–311View ArticleGoogle Scholar
- Sato H, Iwasaki T, Kawasaki S et al (2004) Formation and shortening deformation of a back-arc rift basin revealed by deep seismic profiling, central Japan. Tectonophysics 388:47–58. doi:10.1016/j.tecto.2004.07.004 View ArticleGoogle Scholar
- Sato H, Taniguchi H (1997) Relationship between crater size and ejecta volume of recent magmatic and phreato-magmatic eruptions: implications for energy partitioning. Geophys Res Lett 24:205–208. doi:10.1029/93GL02142 View ArticleGoogle Scholar
- Seno T (2012) Great earthquakes along the Nankai Trough: a new idea for their rupture mode and time series (in Japanese with English abstract). Zisin 64:97–116View ArticleGoogle Scholar
- Suzuki Y, Fujii T (2010) Effect of syneruptive decompression path on shifting intensity in basaltic sub-Plinian eruption: Implication of microlites in Yufune-2 scoria from Fuji volcano, Japan. J Vol Geotherm Res 198:158–176View ArticleGoogle Scholar
- Takada A, Ishizuka Y, Nakano S, et al (2007) Characteristic and evolution inferred from eruptive fissures of Fuji volcano, Japan (in Japanese with English abstract). In: Aramaki S, Fujii T, Nakada S, Miyaji N (eds) Fuji Volcano. Yamanashi Institute of Environmental Sciences, pp 183–202
- Toramaru A (2014) On the second nucleation of bubbles in magmas under sudden decompression. Earth Planet Sci Lett 404:190–199View ArticleGoogle Scholar
- Tsuya H (1955) Geological and petrological studies of volcano, Fuji, V.: 5. On the 1707 eruption of Volcano Fuji. Bull Earthquake Res Inst 64:341–383Google Scholar
- Ukawa M (1991) Collision and fan-shaped compressional stress pattern in the Izu Block at the northern edge of the Philippine Sea Plate. J Geophys Res 96:713–728. doi:10.1029/90JB02142 View ArticleGoogle Scholar
- Urbain G, Bottinga Y, Richet P (1982) Viscosity of liquid silica, silicates and alumino-silicates. Geochim Cosmochim Acta 46:1061–1072. doi:10.1016/0016-7037(82)90059-X View ArticleGoogle Scholar
- Utsu T (1961) A statistical study on the occurrence of aftershocks. Geophys Mag 30:521–605Google Scholar
- Walter TR, Amelung F (2007) Volcanic eruptions following M ≥ 9 megathrust earthquakes: implications for the Sumatra-Andaman volcanoes. Geology 35:539–542. doi:10.1130/G23429A.1 View ArticleGoogle Scholar
- Wessel P, Smith WHF (1995) New version of the generic mapping tools released. Eos Trans AGU 76:329. doi:10.1029/95EO00198 View ArticleGoogle Scholar