################################################################################ MODELLING GROUND DISPLACENT AND GRAVITY CHANGES AT SOLFATARA CRATER The problem is from: Rinaldi et al. 2011 Electrical conductivity, ground displacement, gravity changes, and gas flow at Solfatara crater (Campi Flegrei caldera, Italy): Results from numerical modeling. J. Volcanol. Geothermal Res. 207, 93-105. See description at: 1. http://dx.doi.org/10.1016/j.jvolgeores.2011.07.008 2. http://dx.doi.org/10.1016/j.pepi.2009.09.005 3. http://dx.doi.org/10.1029/2008JB006134 ================================================================================ We assume that 1 month=30.4375 days. RUNSPEC ################### RUNSPEC section begins here ###################### ^^^^^^^^^^^^^^^^^^^^^^^^^^^ We use the BINMIXT EOS-module ^^^^^^^^^^^^^^^^^^^^^^ METRIC ^^^^^^^^^^^^ We use METRIC units ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ HCROCK We enable the heat fluxes due to thermal conductivity. GRAVIMET We enable the calculation of the gravity -- mode scale changes. AXISYM 100 / The data items have the following meaning: 1. AXISYM - the calculation accounts or the rotational symmetry. By default the coordinates of the vertical axis of symmetry are x=0 m and y=0 m. 2. Scale=100 means that 1/100th of the full circle is simulated. GRDDISP We enable the calculation of the ground -- mode scale displacement. AXISYM 100 / The data items have the following meaning: 1. AXISYM - the calculation accounts or the rotational symmetry. By default the coordinates of the vertical axis of symmetry are x=0 m and y=0 m. 2. Scale=100 means that 1/100th of the full circle is simulated. STARTTIM Initial moment of time = -4000 yr=-1461000 days. -1461000 / GRID ##################### GRID section begins here ####################### The grid is specified within brackets MAKE-ENDMAKE MAKE <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< -- grid -- type nr ntheta nz We choose the radial grid and specify RADIAL 60 1 15 / the number of grid blocks along each axis. RTZBOUND -- rmin rmax thetamin thetamax zmin zmax 0 10000 -0.03141 0.03141 0 1500 1.025 1* 1.05 / We specify the boundaries of the domain. We use refined grid near the axis of symmetry and the surface. 1/100-th of the full circle is simulated. BOUNDARY 102 6* K- 5* INFTHIN 1* 3* 1* 2 / We create the ghost grid blocks for 103 6* K+ 5* INFTHIN 1* 3* 2 2 / the boundary conditions. The / elements at the top surface are distinguished by FLUXNUM=102. The impermeable elements at the bottom boundary are distinguished by FLUXNUM=103. SRCSPECG We create the point source at MYSRC 3* 1 0 1499 / x=1 m, y=0 m, z=1499 m. Thus, the / point source is located in the lower left grid block. ENDMAKE >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> OBSPOINT We create the observation point named -- name x y z CENTRE. The point is at the surface on CENTRE 0 0 0 / the axis of rotation. / OBSSPECM TOP 1 1000 0 10000 1 2*0 1 2*0 / / We create the network of observation points along the straight line y=0, z=0. There are 1000 observation points equally spaced between x=0 m and x=10000 m. EQUALS We equal: PORO 0.2 / - porosity to 0.2, PERMI 10 / - horizontal permeability to 10 mD, PERMK 10 / - vertical permeaibility to 10 mD, HCONDCFI 2.8 / - horizontal and vertical thermal HCONDCFK 2.8 / conductivity to 2.8 W/m/K. / RPTGRID We report the distributions of these PORO PERMI PERMK / properties from the GRID section. PROPS ####################### PROPS section begins here #################### Rock properties are specified within brackets ROCK-ENDROCK ROCK <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< / ROCKDH -- ---- rock ---- -- density (kg/m3) heat capacity (kJ/kg/K) 2000 1.0 / GRDPARAM -- shear drained bulk modulus thermal exp. -- modulus bulk modulus of the solid coefficient -- (GPa) (GPa) (GPa) (1/K) 2.0 5.0 30.0 1E-5 / By using this keyword we specify the parameters of rock required for the ground displacement modelling. ENDROCK >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LOADEOS '../../INCLUDE/CO2H2O_V3.0.EOS' / We load CO2-H2O mixture properties file. The relative permeabilities are specified within brackets SAT-ENDSAT SAT <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< / SATTAB -- sliq krliq krgas 0.3 0.0 1.0 / We specify the relative permeability 0.35 0.000035 0.847029 / functions. Corey's curves with 0.4 0.000560 0.699030 / smin=0.3, smax=0.95. 0.45 0.002836 0.560204 / 0.5 0.008963 0.433913 / 0.55 0.021882 0.322677 / 0.6 0.045376 0.228178 / 0.65 0.084065 0.151255 / 0.7 0.143412 0.091908 / 0.75 0.229718 0.049297 / 0.8 0.350127 0.021742 / 0.85 0.512622 0.006722 / 0.9 0.726024 0.000875 / 0.95 1.0 0.0 / / ENDSAT >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> PHASES -- name pres enth CO2 H2O We define the typical parameters of GAS 10 45 0.5 0.5 / the gas phase (GAS). These are used for / reporting the property SAT#GAS. INIT ####################### INIT section begins here ##################### REGALL ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The following keywords will be applyied to both internal and boundary grid blocks. OPERAREG -- modified argument marker opera paramet paramet paramet -- property property marker value tion er1 er2 er3 -- -------- -------- --------- --------- -------- -------- -------- --------- PRESSURE DEPTH INCONUM 1 MULTA 1 0.1 / TEMPC DEPTH INCONUM 1 MULTA 20 0.05 / -- -------- -------- --------- --------- -------- -------- -------- --------- / The OPERAREG keyword does the following: -- PRESSURE=1+0.1*DEPTH -- TEMPC=20+0.05*DEPTH EQUALREG -- new -- property value marker marker value -- -------- -------- --------- --------- COMP1T 0.0 INCONUM 1 / The initial CO2 concentration is 0. -- -------- -------- --------- --------- / EQUALNAM -- new -- property value template Here, we specify the parameters of the -- -------- -------- --------- magmatic fluid injected through the PRES 180 MYSRC / point source. Its temperature is TEMPC 350 / 350C at 180 MPa. The molar COMP1T 0.145299 / concentration of CO2 is 0.145299. -- -------- -------- --------- / RPTSUM PRES TEMPC COMP1T PHST SAT#GAS X12#GAS TEMP DENT DDENGRAV DVOLDISP / We report the distributions of these parameters. RPTSRC We report these properties of the SMIR#1 SMIR#2 / point source. RPTOBS We report these parameters in GRAVMTX GRAVMTZ GRAVMT UX UZ XOBS YOBS / every observation point. GRAVMT# - the gravity change along each axis; U# - the ground displacement along each axis; XOBS - the X coordinate of observation point. SCHEDULE #################### SCHEDULE section begins here ################### ILUTFILL 5 / ILUTDROP 1E-5 / VARS PRES DMAX 50 / The maximum pressure change is 50 bar. / REPORTS No reports to the LOG-file. NOTHING / Here, we simulate the quite period before the unrest event. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< QUIET <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< SRCINJE MYSRC MASS 1* 500 1* 34 / The injection rate is 34 ton/day. / TUNING The maximum time step is 10 years. 1* 3652.5 / TSTEP We proceed simulation to 400 yr 146100 / TUNING The maximum time step is 100 years. 1* 36525 / TSTEP We proceed simulation to 4000 yr, reporting 9*146100 / every 400 yr=146100 days. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SETDGRAV The current distribution of density will be used as the reference for the gravity changes. SETREFPT The current distribution of pressure and temperature will be used as the reference for the gravity changes. Here, we simulate the unrest. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<< UNREST <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< RESETNAM MYSRC / We reset parameters in the stock tank associated / with the point source EQUALNAM -- new -- property value template -- -------- -------- --------- PRES 180 MYSRC / Now, the concentration of CO2 in the TEMPC 350 / injected fluid is 0.285714. COMP1T 0.285714 / -- -------- -------- --------- / UPDATNAM We initialize parameters in the stock tank MYSRC / (primary variables->secondary variables). / SRCINJE MYSRC MASS 1* 500 1* $D#RATE / We place the declaration in place / of the degassing rate. The declaration is changed to a numeric value when the Utilities program transforms the template to RUN-file. TSTEP We simulate injection over 20 month. 1 29.4375 19*30.4375 / >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Now, the period of dormancy begins. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<< QUIET <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< RESETNAM MYSRC / We reset parameters in the stock tank associated / with the point source EQUALNAM -- new -- property value template -- -------- -------- --------- PRES 180 MYSRC / The concentration of CO2 in the TEMPC 350 / injected fluid is reduced back to COMP1T 0.145299 / 0.145299. -- -------- -------- --------- / UPDATNAM We initialize parameters in the stock tank MYSRC / (primary variables->secondary variables). / SRCINJE MYSRC MASS 1* 500 1* 34 / The injection rate is 34 ton/day. / TSTEP We simulate the magma degassing over 100 months. 1 29.4375 99*30.4375 / >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> POST ####################### POST section begins here ##################### <<<<<<<<<<<<<<<<<<<<<<< Here, we specify the objective function <<<<<<<<<<<<<<<< FUNCNAME 11 / INCLUDE We create the user's function '../GRAVMTZ-OBS.TXT' / gravmtz(timey). The function name is 11. The function describes the observed gravity changes in CENTRE. FUNCNAME 12 / INCLUDE We create the user's function '../UZ-OBS.TXT' / uz(timey). The function name is 12. The function describes the observed vertical displacement in CENTRE. OBJTOBS -- obs. point weight prop-X prop-Y UserFunc FirstFrame LastFrame CENTRE 0.1 TIMEY GRAVMTZ 11 11 132 / CENTRE 1.0 TIMEY UZ 12 11 132 / / Here, we specify the objective function. The 1st line add the simulation data deviation from the observations for the gravity changes. The 2nd line does the same for the vertical displacement at x=0, z=0. RPTOBJ We report the objective functions to / the OBJ-file >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> END ######################################################################