Journal
EARTH PLANETS AND SPACE
Volume 66, Issue -, Pages -Publisher
SPRINGER HEIDELBERG
DOI: 10.1186/s40623-014-0158-y
Keywords
Magnetotellurics; 3-D modeling; Saline fluids; Northeastern Japan; Quaternary volcanoes; Seismicity
Categories
Funding
- JSPS KAKENHI Grant [21109003]
- Grants-in-Aid for Scientific Research [26109006, 21109003] Funding Source: KAKEN
Ask authors/readers for more resources
We analyzed the 3-D resistivity structure beneath Naruko volcano, northeastern Japan, with the aim of imaging 3-D distribution of fluids in the crust for its volcanic and seismogenic implications. The data were recorded at 77 sites in total: 30 sites are new and are arranged in an approximately 5 x 5 km grid whereas the remaining older sites constitute two separate east-west profiles. We ran a 3-D inversion using full components of impedance tensors in the period range between 0.13 and 400 s. The resulting model showed that a sub-vertical conductor exists a few kilometers below Naruko volcano. The conductor extends from the surface of the volcano and dips towards the south, away from the volcano towards the backbone range. High levels of seismicity are observed in the upper crust above and around the conductors. We suggest that the seismicity is fluid driven and that a fluid trap is created by the precipitation of quartz owing to a reduction in solubility at shallow depth. The Quaternary volcanic front is characterized by a sharp resistivity contrast and a high-resistivity zone and extends 10 to 15 km towards the east. A fore-arc conductor was observed at mid-crustal levels even farther towards the east. The sub-vertical conductors along the arc and the fore-arc conductor have resistivities of 1 to 10 Omega m. Assuming a Hashin-Shtrikman model with saline fluids of 0.1-Omega m resistivity, a porosity of 1.5% to 15% is required to explain the observed conductive anomalies.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available