WEKO3
アイテム
Surface CO<inf>2</inf>emission and rising bubble plumes from degassing of crater lakes in Sao Miguel Island, Azores
https://nied-repo.bosai.go.jp/records/4914
https://nied-repo.bosai.go.jp/records/49142dd002bd-f60a-4f57-a977-b3b6f4c811de
| Item type | researchmap(1) | |||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 公開日 | 2023-03-30 | |||||||||||||||||||||||||||||||||||||
| タイトル | ||||||||||||||||||||||||||||||||||||||
| 言語 | ja | |||||||||||||||||||||||||||||||||||||
| タイトル | Surface CO<inf>2</inf>emission and rising bubble plumes from degassing of crater lakes in Sao Miguel Island, Azores | |||||||||||||||||||||||||||||||||||||
| タイトル | ||||||||||||||||||||||||||||||||||||||
| 言語 | en | |||||||||||||||||||||||||||||||||||||
| タイトル | Surface CO2 emission and rising bubble plumes from degassing of crater lakes in Sao Miguel Island, Azores | |||||||||||||||||||||||||||||||||||||
| 言語 | ||||||||||||||||||||||||||||||||||||||
| 言語 | eng | |||||||||||||||||||||||||||||||||||||
| 著者 |
Meli{\'a}n G
× Meli{\'a}n G
× Somoza L
× Padr{\'o}n E
× P{\'e}rez N.M
× Hern{\'a}ndez P.A
× Sumino H
× Forjaz V.H
× Fran?a Z
|
|||||||||||||||||||||||||||||||||||||
| 抄録 | ||||||||||||||||||||||||||||||||||||||
| 内容記述タイプ | Other | |||||||||||||||||||||||||||||||||||||
| 内容記述 | We report the first detailed study on the types and distributions of active subaqueous fumaroles and surface diffuse CO2 degassing in the three main volcanic lakes of Sao Miguel Island (Sete Cidades, Fogo and Furnas), Azores archipelago, Portugal. The results of the surveys, carried out in May 2011 using a floating accumulation chamber and a dual beam 50 and 200 kHz echo sounder, revealed a very low surface CO2 degassing at the three lakes, in the range of 32-608 kg d-1. However, dense subaqueous degassing plumes were found in the north of the Furnas crater lake (7.5-9 plumes per 100 m2), and moderate-density degassing in the Fogo (1.5-2 plumes per 100 m2) and Sete Cidades crater lakes (1-1.5 plumes per 100 m2). The echo sounder detected hydroacoustic signatures interpreted as acoustic flares, ≪puffing≫ bubble plumes or walls of bubbles associated with numerous subaqueous fumaroles. The recorded echograms show that the bubbles rise at average speeds of between 19 and 30 cm s-1 at the bottom, with frequencies of release from 1-2 to 31 s. Most subaqueous fumaroles disappear due to the dissolution of CO2 before reaching the lake surface. These dissolution processes are enhanced by the pH range observed in the three volcanic lakes (c. 7-9). Observed dissolved CO2 values indicate that the pressure of this gas in the three lakes remained much lower than the hydrostatic pressure and the risk of a limnic eruption is therefore negligible. We suggest that the rising levels of CO2 from the subaqueous bubbles could constitute a critical fuel for subsurface phytoplankton layers, interpreted as horizontal acoustic layers with high backscattering values. The highest density of subaqueous bubbling correlates with recent submerged secondary craters formed around the caldera rims of the three Late Quaternary stratovolcano complexes of Sao Miguel Island. Our results emphasize the need to perform regular surface degassing studies as an important volcanic surveillance tool in the Azores archipelago. | |||||||||||||||||||||||||||||||||||||
| 言語 | en | |||||||||||||||||||||||||||||||||||||
| 書誌情報 |
ja : Geological Society Special Publication en : Geological Society Special Publication 巻 437, 号 1, p. 233-252, 発行日 2017-05 |
|||||||||||||||||||||||||||||||||||||
| 出版者 | ||||||||||||||||||||||||||||||||||||||
| 言語 | en | |||||||||||||||||||||||||||||||||||||
| 出版者 | Geological Society of London | |||||||||||||||||||||||||||||||||||||
| ISSN | ||||||||||||||||||||||||||||||||||||||
| 収録物識別子タイプ | ISSN | |||||||||||||||||||||||||||||||||||||
| 収録物識別子 | 0305-8719 | |||||||||||||||||||||||||||||||||||||
| DOI | ||||||||||||||||||||||||||||||||||||||
| 関連識別子 | 10.1144/SP437.14 | |||||||||||||||||||||||||||||||||||||
