Vertical ground deformation related to the 2014 and 2015 eruptions at Kuchierabujima Volcano, Japan detected by repeated precise leveling surveys

Yamamoto, Koki; Ohkura, Takahiro; Yokoo, Akihiko; Tameguri, Takeshi; Sonoda, Tadaomi; Inoue, Hiroyuki

doi:10.2328/jnds.38.133

Cited by 17 publications

(18 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The pattern of horizontal displacements shows a WNW-ESE extension, which suggests a tensile fault rather than the isotropic pressure source implied from radial displacement patterns around Sakurajima and the Aira caldera in previous studies which located pressure sources beneath the Aira caldera, Kita-dake and Minami-dake (e.g., Iguchi et al 2013;Yamamoto et al 2013;Hotta et al 2016). Thus, we applied the dislocation source model for a half-infinite homogeneous elastic solid with a Poisson coefficient of 0.25 (Okada 1992).…”

Section: Analysis and Resultsmentioning

confidence: 59%

See 1 more Smart Citation

Rapid dike intrusion into Sakurajima volcano on August 15, 2015, as detected by multi-parameter ground deformation observations

2016

Self Cite

View full text Add to dashboard Cite

We present observations of ground deformation at Sakurajima in August 2015 and model the deformation using a combination of GNSS, tilt and strain data in order to interpret a rapid deformation event on August 15, 2015. The pattern of horizontal displacement during the period from August 14 to 16, 2015, shows a WNW-ESE extension, which suggests the opening of a dike. Using a genetic algorithm, we obtained the position, dip, strike length, width and opening of a dislocation source based on the combined data. A nearly vertical dike with a NNE-SSW strike was found at a depth of 1.0 km below sea level beneath the Showa crater. The length and width are 2.3 and 0.6 km, respectively, and a dike opening of 1.97 m yields a volume increase of 2.7 × 10 6 m 3 . 887 volcano-tectonic (VT) earthquakes beside the dike suggest that the rapid opening of the dike caused an accumulation of strain in the surrounding rocks, and the VT earthquakes were generated to release this strain. Half of the total amount of deformation was concentrated between 10:27 and 11:54 on August 15. It is estimated that the magma intrusion rate was 1 × 10 6 m 3 /h during this period. This is 200 times larger than the magma intrusion rate prior to one of the biggest eruptions at the summit crater of Minami-dake on July 24, 2012, and 2200 times larger than the average magma intrusion rate during the period from October 2011 to March 2012. The previous Mogi-type ground deformation is considered to be a process of magma accumulation in preexisting spherical reservoirs. Conversely, the August 2015 event was a dike intrusion and occurred in a different location to the preexisting reservoirs. The direction of the opening of the dike coincides with the T-axes and direction of faults creating a graben structure.

show abstract

Section: Analysis and Resultsmentioning

confidence: 59%

“…Previously, a combination of spherical sources in an elastic and homogeneous half-space (Mogi 1958) was applied to the observed deformation in and around Sakurajima (e.g., Iguchi et al 2013;Yamamoto et al 2013;Hotta et al 2016). The ground deformation during these observation periods had characteristics suggestive of isotropic sources.…”

Section: Discussionmentioning

confidence: 99%

Rapid dike intrusion into Sakurajima volcano on August 15, 2015, as detected by multi-parameter ground deformation observations

2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Because of the eruption disasters that occurred in 2014 and 2015, among the baselines between GNSS stations on the volcano, we could only identify one temporal baseline length change (JMA station) and no clear baseline length changes were recorded during our OBS observation period (Fukuoka Volcanic Observation and Information Center and Kagoshima Meteorological Observatory, 2016), which is consistent with the scarcity of DVT earthquakes throughout the period. As for the volcano's main reservoir, Yamamoto et al (2017) performed repeated precise leveling surveys in order to estimate pressure sources. Assuming that the pressure source was located under Mt.…”

Section: Discussionmentioning

confidence: 99%

Seismic Observations using Ocean Bottom Seismometers around Kuchierabujima Volcano

Yakiwara

Kanehara

Nakao

et al. 2017

Journal of Natural Disaster Science

View full text Add to dashboard Cite

The remarkable eruption on Kuchierabujima, which occurred on May 29, 2015, had the potential to disrupt land seismic observation if the volcanic activities had expanded. Since relatively deep-volcano-tectonic (DVT) earthquakes under the volcano may have extended into the sea region around the island, we deployed four ocean bottom seismometers (OBSs) on the seafloor at distances at approximately 6.5 km from the crater. During the OBS observation period from July 3 to October 9, 2015, 303 volcanic earthquakes were detected. The daily numbers and the temporal amplitude changes indicate that seismic activities declined in the middle of August. However, only nine of the events were DVT earthquakes, and we were unable to identify any clear differences between the hypocenter distribution characteristics of the DVT events discussed in previous studies and those of our observations. However, since the temporal tendency of daily earthquake numbers derived from our OBS data resembled that compiled by the Japan Meteorological Agency using real-time land data, when eruption expansions occur on a small-scale remote island such as Kuchierabujima, OBS observations can provide a useful backup to efforts aimed at grasping the seismicity.

show abstract

“…Some volcanoes show the pressure accumulation between eruptions or eruptive phases, for example, Sakurajima (Yamashina 2013;Yamamoto et al 2013) and Krafla (Tryggvason 1995;Sturkell et al 2006), but such signals are not always present on Fogo and Furnas. The absence of edifice-scale deformation on Fogo and Furnas volcanoes suggests there were no significant pressure changes under these volcanoes during this period.…”

Section: Volcanic Implicationsmentioning

confidence: 99%

Chapter 18 Tectonic and volcanic deformation at São Miguel Island, Azores, observed by continuous GPS analysis 2008–13

Okada

Sigmundsson

Ófeigsson

et al. 2015

Memoirs

View full text Add to dashboard Cite

We use a Global Positioning System (GPS) to unravel the complex geodynamics of the Azores Triple Junction where tectonic and volcanic activities coexist. The temporal analysis of densely distributed continuous GPS data on São Miguel for the period 2008-13 provides an improved understanding of interactions between present-day plate boundary kinematics and volcanic deformation. We find a high-strain-rate (0.28 ppm a -1 ) zone between Congro and Furnas, which accommodates about 50% of the Eurasian-Nubian plate spreading as predicted by the MORVEL plate angular velocity model. The seismic unrest of Fogo-Congro (2011-12) shows a strong similarity with the Matsushiro (Japan) earthquake swarm (1965-66) and the Campi Flegrei (Italy) volcanic unrest (1969-72 and 1982-85), in that an edifice-scale inflation associated with intense high-frequency earthquakes and inflation-deflation reversals coincided with a sharp drop in seismicity. We propose the following hypothesis for the Fogo unrest: (1) the primary inflation source beneath Fogo promotes lateral diffusion of fluids that is selectively guided by existing cracks/fissures formed from regional extension;(2) an influx of fluids increases pressure in cracks/fissures and generates lower-frequency earthquakes; and (3) discharge of fluids causes pressure decrease and dilatancy recovery (i.e. seismic quiescence).

show abstract

Vertical ground deformation related to the 2014 and 2015 eruptions at Kuchierabujima Volcano, Japan detected by repeated precise leveling surveys

Abstract: We conducted precise leveling surveys in Kuchierabujima Volcano, southwest Japan seven times after

Cited by 17 publications

References 12 publications

Rapid dike intrusion into Sakurajima volcano on August 15, 2015, as detected by multi-parameter ground deformation observations

Rapid dike intrusion into Sakurajima volcano on August 15, 2015, as detected by multi-parameter ground deformation observations

Seismic Observations using Ocean Bottom Seismometers around Kuchierabujima Volcano

Chapter 18 Tectonic and volcanic deformation at São Miguel Island, Azores, observed by continuous GPS analysis 2008–13

Contact Info

Product

Resources

About