Variable inflation rate of a magmatic deformation source beneath Aira caldera after the 1914 eruption of Sakurajima volcano: Inferences from a linear Maxwell viscoelastic model constrained by geodetic data

Assessing the Multiple Pressure Source Hypothesis for the Sakurajima Volcano and Aira Caldera Magmatic System

10.5194/egusphere-egu21-14799 ◽

2021 ◽

Author(s):

Robert Backhurst

Keyword(s):

Numerical Modelling ◽

Large Scale ◽

Numerical Study ◽

Deformation Source ◽

Geodetic Data ◽

Analytical Models ◽

Magmatic System ◽

Sakurajima Volcano ◽

Subsurface Heterogeneity ◽

Increased Risk

Sakurajima, located on the southern rim of Aira caldera, is one of the most active volcanoes in Japan. From long term deformation trends, the volcano is showing an increased risk of large-scale eruption, emphasizing the need to better understand the magmatic system.Deformation modelling, primarily using the Mogi method, has dominated the geodetic assessment history of Sakurajima. These methods, however, contain limitations, such as the assumption of a homogeneous crust, and have therefore not accurately depicted the magmatic system. Numerical modelling techniques have reduced this limitation by accounting for subsurface heterogeneity.Analytical modelling studies have suggested multiple magmatic sources beneath Aira caldera and Sakurajima volcano, whilst the only numerical study undertaken so far indicated a single source. Here, we test the multiple deformation source hypothesis, whilst also incorporating subsurface heterogeneity and topography, using Finite Element (FE) numerical modelling, and geodetic data from Sakurajima.Using a full 3D model geometry for Sakurajima and Aira caldera, preliminary forward modelling suggests a second deformation source produces our best fit to the measured geodetic data. Optimum results indicate a shallow prolate source 7-10 km below sea level (bsl), in addition to a deeper oblate source at ~13 km bsl. These preliminary findings produce greater shallow storage depths than the previous analytical models (3-6 km) and ties in with the trans-crustal magmatic system hypothesis.Increasing our understanding of the Sakurajima magmatic system will enable improved interpretations of geodetic data prior to eruptions and will inform models for a range of similar volcanoes world-wide.

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Viscoelastic crustal deformation in the Aira caldera before and after the 1914 eruption of the Sakurajima volcano

10.5194/egusphere-egu2020-2236 ◽

2020 ◽

Author(s):

Tadashi Yamasaki ◽

Freysteinn Sigmundsson ◽

Masato Iguchi

Keyword(s):

Elastic Layer ◽

Inflation Rate ◽

Viscoelastic Model ◽

Geodetic Data ◽

Viscoelastic Layer ◽

Elastic Model ◽

Viscoelastic Response ◽

Volcano Deformation ◽

Surface Uplift ◽

Magma Supply

Long-term volcano deformation cannot be well understood without considering crustal viscoelasticity because the presence of magma is expected to significantly lower the crustal viscosity beneath volcanoes. In this study, we examine viscoelastic crustal response to continuous magma supply into the upper crust and its sudden discharge. We use a three-dimensional (3-D) finite element model composed of an elastic layer underlain by a linear Maxwell viscoelastic layer with spatially uniform viscosity, in which a sill emplaced at the bottom of the elastic layer inflates with constant rate, during which the deflation due to an eruption suddenly occurs. Our numerical experiment finds that viscoelastic response to the sill deflation causes post-eruption surface uplift, depending on how much viscoelastic relaxation progresses in response to sill inflation due to pre-eruption magma supply and how much the sill deflates during the eruption. However, the recovery of the post-eruption surface is always later than that of the sill volume, because the viscoelastic response to the sill inflation reduces the surface uplift. Magma recharge is required to bring the surface to the elevation that was at immediately before the eruption. We adopt our viscoelastic model to geodetic data in and around the Aira caldera, southern Kyushu, Japan. It is found that the observed exponential-like surface recovery after the 1914 eruption can be explained if: (1) The effective crustal viscosity is &#8764;5&#215;1018 Pa s, (2) the sill emplacement, whose equatorial radius is &#8764;2 km, occurs at a depth of &#8764;11 km, (3) a constant inflation rate of the sill is &#8764;0.009 km3/yr, which has continued since &#8764;50 yr before the 1914 eruption, and (4) the sill deflates by &#8764;0.4 km3 during the 1914 eruption, &#8764;4 times less than the eruptive volume. The sill inflation during the first &#8764;50 yr after the eruption is lower than that predicted by an elastic model, but larger thereafter. Fit to geodetic data after &#8764;1975 can be improved by introducing temporal variation of the inflation rate, which is a topic of investigation for a future study.

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Tectonic plate coupling and elastic thickness derived from the inversion of a steady state viscoelastic model using geodetic data: Application to southern North Island, New Zealand

Journal of Geophysical Research Atmospheres ◽

10.1029/2001jb001687 ◽

2003 ◽

Vol 108 (B3) ◽

Cited By ~ 5

Author(s):

Steven C. Cohen ◽

Desmond J. Darby

Keyword(s):

Steady State ◽

New Zealand ◽

Viscoelastic Model ◽

Geodetic Data ◽

Tectonic Plate ◽

Data Application ◽

Plate Coupling

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Laboratory testing to develop a non-linear viscoelastic model for rutting of asphalt concrete

Sixth International RILEM Symposium on Performance Testing and Evaluation of Bituminous Materials ◽

10.1617/2912143772.063 ◽

2003 ◽

Author(s):

F. Long

Keyword(s):

Asphalt Concrete ◽

Laboratory Testing ◽

Viscoelastic Model ◽

Non Linear ◽

Linear Viscoelastic ◽

Linear Viscoelastic Model

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ECONOMIC GROWTH ANALYSIS: A STUDY ON MALAYSIAN MARKET

e-Academia Journal ◽

10.24191/e-aj.v9i2.7379 ◽

2019 ◽

Vol 8 (2) ◽

Author(s):

Suhaily Maizan Abdul Manaf ◽

Shuhada Mohamed Hamidi ◽

Nur Shafini Mohd Said ◽

Siti Rapidah Omar Ali ◽

Nur Dalila Adenan

Keyword(s):

Economic Growth ◽

Foreign Direct Investment ◽

Direct Investment ◽

Inflation Rate ◽

Government Expenditure ◽

Correlation Method ◽

Research Direction ◽

Least Square ◽

Future Research ◽

Internal And External Factors

Economic performance of a country is mostly determined by the growth and any other internal and external factors. In this study, researchers purposely focused on Malaysian market by examining the relationship between export, inflation rate, government expenditure and foreign direct investment towards economic growth in Malaysia by applying the yearly data of 47 years from 1970 to 2016 using descriptive statistics, regression model and correlation method analysis. By applying Ordinary Least Square (OLS) method, the result suggests that export, government expenditure and foreign direct investment are positively and significantly correlated with the economic growth. However, inflation rate has negative and insignificant relationship with the economic growth. The outcome of the study is suggested to be useful in providing the future research direction towards the economic growth in Malaysia. Keywords: economic growth; export; inflation rate; government expenditure

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CONSTRUCTION OF FORECAST MODEL BY THE SEARCH METHOD OF NONLINEAR PROGRAMMING ON GEODETIC DATA

10.25296/1997-8650-2019-13-4-48-58 ◽

2019 ◽

Vol XIII (4/2019) ◽

Keyword(s):

Nonlinear Programming ◽

Forecast Model ◽

Search Method ◽

Geodetic Data

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THERMO-VISCOELASTIC MODEL FOR THE CONTRACTION DURING THE POLYMERIZATION OF BULK FILL RESINS

10.26678/abcm.enebi2018.eeb18-0124 ◽

2018 ◽

Author(s):

Claudio Antunes Junior ◽

Emílio Mercuri ◽

Ana Paula Gebert de Oliveira Franco ◽

Leandro Zen Karam

Keyword(s):

Viscoelastic Model

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IMF Stabilization Programs, Policy Conduct and Macroeconomic Outcomes: A Case Study of Pakistan

THE LAHORE JOURNAL OF ECONOMICS ◽

10.35536/lje.2006.v11.i1.a3 ◽

2006 ◽

Vol 11 (1) ◽

pp. 35-62

Author(s):

Nawaz A. Hakro ◽

Wadho Waqar Ahmed

Keyword(s):

Current Account ◽

Inflation Rate ◽

Current Account Balance ◽

Macroeconomic Policies ◽

Explanatory Variables ◽

Fiscal Balance ◽

Macroeconomic Impacts ◽

The Individual ◽

The Imf

This study is designed to assess the macroeconomic performance of fund-supported programs, and the sequencing and ordering of macroeconomic policies in the context of the Pakistan economy. The generalized evaluation estimator technique has been used to assess the macroeconomic impacts of the IMF supported programs. GDP growth, inflation rate, current account balance, fiscal balance and unemployment are used as the target variables in order to gauge economic performance during the program years. The vector of policy variables (that might have been adopted in the absence of programs) and the vector of foreign exogenous variables are also taken as explanatory variables in the model, so that the individual effect of the IMF supported programs could be assessed. The result suggests that as the IMF prescriptions were applied, the current account balance has worsened, the unemployment rate has significantly increased, and the inflation rate has increased during the years of fund-supported programs. Only the budget balance has shown signs of improvement. Furthermore an inadequate sequencing of reforms has contributed to the further worsening of the economic scenario during the program period.

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