Dear all,

I am running a model using a free surface, but I get an error that I do not understand when the simulation reaches ~4 million years. I guess the problem is due to the sudden change in topography, but I would like to know if anyone knows how to solve this problem. The error message is as follows:

**ERROR MESSAGE:**

*** Timestep 2837: t=4.64329e+06 years, dt=276.765 years

Solving mesh velocity system… 6 iterations.

Solving temperature system… 1 iterations.

Solving oceanic_crust system … 0 iterations.

Solving continental_uppercrust system … 1 iterations.

Solving continental_lowercrust system … 1 iterations.

Solving lith system … 1 iterations.

Rebuilding Stokes preconditioner…

Solving Stokes system… 0+23 iterations.

Relative nonlinear residual (Stokes system) after nonlinear iteration 1: 0.011231

Rebuilding Stokes preconditioner…

Solving Stokes system… 0+9 iterations.

Relative nonlinear residual (Stokes system) after nonlinear iteration 2: 0.00020052

Rebuilding Stokes preconditioner…

Solving Stokes system… 0+5 iterations.

Relative nonlinear residual (Stokes system) after nonlinear iteration 3: 3.76123e-05

Postprocessing:

RMS, max velocity: 0.019 m/year, 0.464 m/year

Temperature min/avg/max: 293.2 K, 1522 K, 1643 K

Topography min/max: -1.147e+04 m, 2092 m

*** Timestep 2838: t=4.64356e+06 years, dt=271.978 years

Solving mesh velocity system… 6 iterations.

mpirun(20952,0x16ba7f000) malloc: can’t allocate region

:*** mach_vm_map(size=1125899906859008, flags: 100) failed (error code=3)

mpirun(20952,0x16ba7f000) malloc: *** set a breakpoint in malloc_error_break to debug

[cvi067114:20952] *** Process received signal ***

[cvi067114:20952] Signal: Segmentation fault: 11 (11)

[cvi067114:20952] Signal code: Invalid permissions (2)

[cvi067114:20952] Failing at address: 0x0

[cvi067114:20952] [ 0] 0 libsystem_platform.dylib 0x000000019bb32c44 _sigtramp + 56

[cvi067114:20952] [ 1] 0 mca_rml_oob.so 0x0000000104fe7d18 orte_rml_oob_send_buffer_nb + 892

[cvi067114:20952] [ 2] 0 libopen-rte.40.dylib 0x000000010469a2fc pmix_server_log_fn + 492

[cvi067114:20952] [ 3] 0 mca_pmix_pmix3x.so 0x0000000104d4cd24 server_log + 804

[cvi067114:20952] [ 4] 0 mca_plog_default.so 0x0000000104f6b8cc mylog + 472

[cvi067114:20952] [ 5] 0 mca_pmix_pmix3x.so 0x0000000104dc8bc8 pmix_plog_base_log + 1140

[cvi067114:20952] [ 6] 0 mca_pmix_pmix3x.so 0x0000000104d91490 pmix_server_log + 1788

[cvi067114:20952] [ 7] 0 mca_pmix_pmix3x.so 0x0000000104d794f4 pmix_server_message_handler + 5092

[cvi067114:20952] [ 8] 0 mca_pmix_pmix3x.so 0x0000000104dd0c64 pmix_ptl_base_process_msg + 632

[cvi067114:20952] [ 9] 0 libevent_core-2.1.7.dylib 0x0000000104845250 event_process_active_single_queue + 520

[cvi067114:20952] [10] 0 libevent_core-2.1.7.dylib 0x00000001048422d4 event_base_loop + 948

[cvi067114:20952] [11] 0 mca_pmix_pmix3x.so 0x0000000104d9bd38 progress_engine + 36

[cvi067114:20952] [12] 0 libsystem_pthread.dylib 0x000000019bae7878 _pthread_start + 320

[cvi067114:20952] [13] 0 libsystem_pthread.dylib 0x000000019bae25e0 thread_start + 8

[cvi067114:20952] *** End of error message ***

zsh: segmentation fault mpirun -np 8 ~/aspect/aspect-release Model_Gibraltar.prm

(base) pedro_gea@cvi067114 Velocidades_Gibraltar %

I copy a part of my input file in case it is helpful:

**A PART OF THE INPUT FILE**

set Dimension = 2

set World builder file = Slab_Geometry.wb

set Nonlinear solver scheme = single Advection, iterated Stokes

set Nonlinear solver tolerance = 1e-4

set Max nonlinear iterations = 10

set CFL number = 0.1

set Pressure normalization = no

subsection Solver parameters

set Composition solver tolerance = 1e-5

set Temperature solver tolerance = 1e-5

subsection Stokes solver parameters

set Linear solver tolerance = 1e-5

set Linear solver A block tolerance = 5e-1

set Linear solver S block tolerance = 1e-6

set Stokes solver type = block AMG

set Number of cheap Stokes solver steps = 0

set GMRES solver restart length = 200

set Maximum number of expensive Stokes solver steps = 1000

set Use full A block as preconditioner = false

end

end

subsection Geometry model

set Model name = box

subsection Box

set X extent = 1320e3

set Y extent = 660e3

set X repetitions = 2

set Y repetitions = 1

end

end

subsection Compositional fields

set Number of fields = 4

set Names of fields = oceanic_crust, continental_uppercrust, continental_lowercrust, lith

end

subsection Initial composition model

set Model name = world builder

end

subsection Boundary composition model

set Fixed composition boundary indicators = bottom

set List of model names = initial composition

end

subsection Material model

set Material averaging = harmonic average

set Model name = visco plastic

subsection Visco Plastic

set Reference temperature = 293

set Reference viscosity = 1e21

set Minimum strain rate = 1.e-20

set Reference strain rate = 1.e-15

set Minimum viscosity = 1e19

set Maximum viscosity = 1e23

set Viscosity averaging scheme = harmonic

set Grain size = 1.0e-2

set Thermal diffusivities = 0.8e-6

set Heat capacities = 1250.

set Densities = 3300, 3000, 2750, 2900, 3300

set Thermal expansivities = 3.5e-5

set Viscous flow law = composite

set Prefactors for dislocation creep = 2.28e-18, 2.5e-23, 2.5e-23, 2.5e-50, 2.28e-18

set Stress exponents for dislocation creep = 3.5, 1, 1, 1, 3.5

set Activation energies for dislocation creep = 480e3, 0, 0, 0, 480e3

set Activation volumes for dislocation creep = 1.1e-5, 0, 0, 0, 1.1e-5

set Prefactors for diffusion creep = 4.7e-16, 2.5e-23, 2.5e-23, 5e-19, 4.7e-16

set Activation energies for diffusion creep = 335e3, 0, 0, 170e3, 335e3

set Activation volumes for diffusion creep = 4e-6, 0, 0, 0, 4e-6

set Grain size exponents for diffusion creep = 3, 0, 0, 7, 3

set Angles of internal friction = 0

set Cohesions = 1e30

end

end

subsection Mesh refinement

set Initial global refinement = 4

set Initial adaptive refinement = 4

set Minimum refinement level = 0

set Normalize individual refinement criteria = true

set Refinement criteria merge operation = max

set Skip solvers on initial refinement = false

set Strategy = viscosity, composition, temperature, density, slope

set Time steps between mesh refinement = 10

set Coarsening fraction = 0.1

set Refinement fraction = 0.9

end

subsection Discretization

subsection Stabilization parameters

set Use limiter for discontinuous composition solution = false

set Use limiter for discontinuous temperature solution = false

set Stabilization method = entropy viscosity

set alpha = 2

set beta = 0.052

set cR = 0.11

set gamma = 0.0

end

end

subsection Mesh deformation

set Mesh deformation boundary indicators = top: free surface & diffusion

subsection Diffusion

set Time steps between diffusion = 5

end

subsection Free surface

set Free surface stabilization theta = 0.8

set Surface velocity projection = vertical

end

end

subsection Boundary velocity model

set Tangential velocity boundary indicators = bottom ,left, right

end

**END OF THE INPUT FILE**

I have been playing with the parameter Free surface stabilization theta, giving it values from 0.5 to 1 but it has not worked. Also, I tested other CL values and tried other values for cR and beta in the subsection Discretization (specifically cR=0.5 and beta=0.078).

Could someone give me some advice on how to improve the behavior of the simulation?

I attach a picture of the simulation before it crashes.

Thank you very much!

Pedro