-
Notifications
You must be signed in to change notification settings - Fork 41
/
example_composite_seismic_velocities.py
179 lines (145 loc) · 6.98 KB
/
example_composite_seismic_velocities.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
# This file is part of BurnMan - a thermoelastic and thermodynamic toolkit for the Earth and Planetary Sciences
# Copyright (C) 2012 - 2015 by the BurnMan team, released under the GNU
# GPL v2 or later.
"""
example_composite_seismic_velocities
------------------------------------
This example shows how to create different minerals, how to compute seismic
velocities, and how to compare them to a seismic reference model.
There are many different ways in BurnMan to combine minerals into a
composition. Here we present a couple of examples:
1. Two minerals mixed in simple mole fractions. Can be chosen from the BurnMan
libraries or from user defined minerals (see example_user_input_material)
2. Example with three minerals
3. Using preset solid solutions
4. Defining your own solid solution
To turn a method of mineral creation "on" the first if statement above the
method must be set to True, with all others set to False.
Note: These minerals can include a spin transition in (Mg,Fe)O, see
example_spintransition.py for explanation of how to implement this
*Uses:*
* :doc:`mineral_database`
* :class:`burnman.composite.Composite`
* :class:`burnman.mineral.Mineral`
* :class:`burnman.solidsolution.SolidSolution`
*Demonstrates:*
* Different ways to define a composite
* Using minerals and solid solutions
* Compare computations to seismic models
"""
from __future__ import absolute_import
from __future__ import print_function
import numpy as np
import matplotlib.pyplot as plt
import burnman_path # adds the local burnman directory to the path
import burnman
from burnman import minerals
assert burnman_path # silence pyflakes warning
if __name__ == "__main__":
# To compute seismic velocities and other properties, we need to supply
# burnman with a list of minerals (phases) and their molar abundances. Minerals
# are classes found in burnman.minerals and are derived from
# burnman.minerals.material.
# Here are a few ways to define phases and molar_abundances:
# Example 1: two simple fixed minerals
if True:
amount_perovskite = 0.95
rock = burnman.Composite([minerals.SLB_2011.mg_perovskite(),
minerals.SLB_2011.periclase()],
[amount_perovskite, 1 - amount_perovskite])
# Example 2: three materials
if False:
rock = burnman.Composite([minerals.SLB_2011.fe_perovskite(),
minerals.SLB_2011.periclase(),
minerals.SLB_2011.stishovite()],
[0.7, 0.2, 0.1])
# Example 3: Mixing solid solutions
if False:
# Defining a rock using a predefined solid solution from the mineral
# library database.
preset_solidsolution = minerals.SLB_2011.mg_fe_perovskite()
# The line below is optional to see which endmembers (and in which order) are in the solid solution
# print preset_solidsolution.endmembers
# Set molar_fraction of mg_perovskite, fe_perovskite and al_perovskite
preset_solidsolution.set_composition(
[0.9, 0.1, 0.]) # Set molar_fraction of mg_perovskite, fe_perovskite and al_perovskite
rock = burnman.Composite(
[preset_solidsolution, minerals.SLB_2011.periclase()], [0.8, 0.2])
# Example 4: Defining your own solid solution
if False:
# Define a new SolidSolution with mg and fe perovskite endmembers
new_solidsolution = burnman.SolidSolution(name = 'New Mg-Fe bridgmanite',
endmembers = [[minerals.SLB_2011.mg_perovskite(),
'[Mg]SiO3'],
[minerals.SLB_2011.fe_perovskite(),
'[Fe]SiO3']],
solution_type = 'ideal')
# Set molar fraction of endmembers
new_solidsolution.set_composition([0.9, 0.1])
rock = burnman.Composite(
[new_solidsolution, minerals.SLB_2011.periclase()], [0.8, 0.2])
# seismic model for comparison:
# pick from .prem() .slow() .fast() (see burnman/seismic.py)
seismic_model = burnman.seismic.PREM()
number_of_points = 20 # set on how many depth slices the computations should be done
# we will do our computation and comparison at the following depth values:
depths = np.linspace(700e3, 2800e3, number_of_points)
# alternatively, we could use the values where prem is defined:
# depths = seismic_model.internal_depth_list(mindepth=700.e3,
# maxdepth=2800.e3)
seis_p, seis_rho, seis_vp, seis_vs, seis_vphi = seismic_model.evaluate(
['pressure', 'density', 'v_p', 'v_s', 'v_phi'], depths)
temperature = burnman.geotherm.brown_shankland(depths)
print("Calculations are done for:")
rock.debug_print()
mat_rho, mat_vp, mat_vphi, mat_vs, mat_K, mat_G = rock.evaluate(
['density', 'v_p', 'v_phi', 'v_s', 'K_S', 'G'], seis_p, temperature)
[vs_err, vphi_err, rho_err] = burnman.tools.compare_chifactor(
[mat_vs, mat_vphi, mat_rho], [seis_vs, seis_vphi, seis_rho])
# PLOTTING
# plot vs
plt.subplot(2, 2, 1)
plt.plot(
seis_p / 1.e9, mat_vs / 1.e3, color='b', linestyle='-', marker='o',
markerfacecolor='b', markersize=4, label='computation')
plt.plot(
seis_p / 1.e9, seis_vs / 1.e3, color='k', linestyle='-', marker='o',
markerfacecolor='k', markersize=4, label='reference')
plt.title("Vs (km/s)")
plt.xlim(min(seis_p) / 1.e9, max(seis_p) / 1.e9)
plt.ylim(5.1, 7.6)
plt.legend(loc='lower right')
plt.text(40, 7.3, "misfit= %3.3f" % vs_err)
# plot Vphi
plt.subplot(2, 2, 2)
plt.plot(
seis_p / 1.e9, mat_vphi / 1.e3, color='b', linestyle='-', marker='o',
markerfacecolor='b', markersize=4)
plt.plot(
seis_p / 1.e9, seis_vphi / 1.e3, color='k', linestyle='-', marker='o',
markerfacecolor='k', markersize=4)
plt.title("Vphi (km/s)")
plt.xlim(min(seis_p) / 1.e9, max(seis_p) / 1.e9)
plt.ylim(7, 12)
plt.text(40, 11.5, "misfit= %3.3f" % vphi_err)
# plot density
plt.subplot(2, 2, 3)
plt.plot(
seis_p / 1.e9, mat_rho / 1.e3, color='b', linestyle='-', marker='o',
markerfacecolor='b', markersize=4)
plt.plot(
seis_p / 1.e9, seis_rho / 1.e3, color='k', linestyle='-', marker='o',
markerfacecolor='k', markersize=4)
plt.title("density ($\cdot 10^3$ kg/m$^3$)")
plt.xlim(min(seis_p) / 1.e9, max(seis_p) / 1.e9)
plt.text(40, 4.3, "misfit= %3.3f" % rho_err)
plt.xlabel("Pressure (GPa)")
# plot geotherm
plt.subplot(2, 2, 4)
plt.plot(seis_p / 1e9, temperature, color='r', linestyle='-', marker='o',
markerfacecolor='r', markersize=4)
plt.title("Geotherm (K)")
plt.xlim(min(seis_p) / 1.e9, max(seis_p) / 1.e9)
plt.xlabel("Pressure (GPa)")
plt.savefig("output_figures/example_composition.png")
plt.show()