mtpy

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mtpy - Magnetotelluric Analysis

mtpy - 大地电磁分析

Quick Reference

快速参考

python

from mtpy import MT, MTCollection

python

from mtpy import MT, MTCollection

Read single station

读取单个测站数据

mt = MT('station001.edi')

Access data

访问数据

Z = mt.Z # Complex impedance tensor freq = mt.frequency # Frequency array rho_xy = mt.apparent_resistivity[:, 0, 1] # Apparent resistivity

Z = mt.Z # 复阻抗张量 freq = mt.frequency # 频率数组 rho_xy = mt.apparent_resistivity[:, 0, 1] # 视电阻率

Station info

测站信息

print(mt.station, mt.latitude, mt.longitude)

Write EDI

写入EDI文件

mt.write_edi('output.edi')

undefined

mt.write_edi('output.edi')

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Key Classes

核心类

Class	Purpose
`MT`	Single station MT data container
`MTCollection`	Multiple stations management
`PlotMTResponse`	Plot impedance, resistivity, phase
`PlotPhaseTensor`	Phase tensor ellipse visualization
`PlotPseudoSection`	Profile pseudosection display
`PlotStrike`	Strike direction analysis

类	用途
`MT`	单个测站MT数据容器
`MTCollection`	多测站数据管理
`PlotMTResponse`	绘制阻抗、电阻率、相位
`PlotPhaseTensor`	相位张量椭圆可视化
`PlotPseudoSection`	剖面拟断面图展示
`PlotStrike`	走向方向分析

Essential Operations

关键操作

Load and Inspect EDI

加载并检查EDI文件

python

from mtpy import MT

mt = MT('station001.edi')
print(f"Station: {mt.station}")
print(f"Location: ({mt.latitude}, {mt.longitude})")
print(f"Frequencies: {len(mt.frequency)} points")
print(f"Period range: {1/mt.frequency.max():.2f} - {1/mt.frequency.min():.0f} s")

python

from mtpy import MT

mt = MT('station001.edi')
print(f"测站: {mt.station}")
print(f"位置: ({mt.latitude}, {mt.longitude})")
print(f"频率点数: {len(mt.frequency)} 个")
print(f"周期范围: {1/mt.frequency.max():.2f} - {1/mt.frequency.min():.0f} 秒")

Load Multiple Stations

加载多个测站数据

python

from mtpy import MTCollection

mc = MTCollection()
mc.from_edis('survey_data/*.edi')
print(f"Loaded {len(mc)} stations")

for station in mc:
    print(f"  {station.station}: ({station.latitude:.4f}, {station.longitude:.4f})")

python

from mtpy import MTCollection

mc = MTCollection()
mc.from_edis('survey_data/*.edi')
print(f"已加载 {len(mc)} 个测站")

for station in mc:
    print(f"  {station.station}: ({station.latitude:.4f}, {station.longitude:.4f})")

Plot MT Response

绘制MT响应曲线

python

from mtpy import MT
from mtpy.imaging import PlotMTResponse

mt = MT('station001.edi')
plot = PlotMTResponse(mt)
plot.plot()  # Apparent resistivity and phase

python

from mtpy import MT
from mtpy.imaging import PlotMTResponse

mt = MT('station001.edi')
plot = PlotMTResponse(mt)
plot.plot()  # 绘制视电阻率和相位

Phase Tensor Analysis

相位张量分析

python

from mtpy import MT
from mtpy.imaging import PlotPhaseTensor

mt = MT('station001.edi')

python

from mtpy import MT
from mtpy.imaging import PlotPhaseTensor

mt = MT('station001.edi')

Get phase tensor parameters

获取相位张量参数

phi_min = mt.phase_tensor.phimin phi_max = mt.phase_tensor.phimax skew = mt.phase_tensor.skew # 3D indicator

phi_min = mt.phase_tensor.phimin phi_max = mt.phase_tensor.phimax skew = mt.phase_tensor.skew # 三维结构指示值

Plot

绘图

pt = PlotPhaseTensor(mt) pt.plot()

undefined

pt = PlotPhaseTensor(mt) pt.plot()

undefined

Rotate Impedance Tensor

旋转阻抗张量

python

from mtpy import MT

mt = MT('station001.edi')
mt_rotated = mt.rotate(30)        # 30 degrees clockwise
mt.rotate_to_strike()             # Auto-rotate to geoelectric strike

python

from mtpy import MT

mt = MT('station001.edi')
mt_rotated = mt.rotate(30)        # 顺时针旋转30度
mt.rotate_to_strike()             # 自动旋转到地电走向

Create Pseudosection

创建拟断面图

python

from mtpy import MTCollection
from mtpy.imaging import PlotPseudoSection

mc = MTCollection()
mc.from_edis('profile/*.edi')

ps = PlotPseudoSection(mc)
ps.plot(plot_type='apparent_resistivity', mode='te')  # or 'tm', 'det'

python

from mtpy import MTCollection
from mtpy.imaging import PlotPseudoSection

mc = MTCollection()
mc.from_edis('profile/*.edi')

ps = PlotPseudoSection(mc)
ps.plot(plot_type='apparent_resistivity', mode='te')  # 可选 'tm'、'det'

Export Data

导出数据

python

from mtpy import MT
import pandas as pd

mt = MT('station001.edi')

python

from mtpy import MT
import pandas as pd

mt = MT('station001.edi')

Export to CSV

导出为CSV

df = pd.DataFrame({ 'frequency': mt.frequency, 'rho_xy': mt.apparent_resistivity[:, 0, 1], 'rho_yx': mt.apparent_resistivity[:, 1, 0], 'phase_xy': mt.phase[:, 0, 1], 'phase_yx': mt.phase[:, 1, 0] }) df.to_csv('mt_data.csv', index=False)

Export for ModEM

导出为ModEM格式

mt.write_modem('station001.dat')

undefined

mt.write_modem('station001.dat')

undefined

Impedance Tensor Components

阻抗张量分量

Component	Description	Mode
Zxx	Ex/Bx response	Diagonal (usually small)
Zxy	Ex/By response	TE mode
Zyx	Ey/Bx response	TM mode
Zyy	Ey/By response	Diagonal (usually small)

分量	描述	模式
Zxx	Ex/Bx响应	对角分量（通常值较小）
Zxy	Ex/By响应	TE模式
Zyx	Ey/Bx响应	TM模式
Zyy	Ey/By响应	对角分量（通常值较小）

Phase Tensor Parameters

相位张量参数

Parameter	Description	Interpretation
phi_min	Minimum phase	Relates to resistivity gradient
phi_max	Maximum phase	Relates to resistivity gradient
skew	Skew angle	>5 suggests 3D structure
ellipticity	(phi_max-phi_min)/(phi_max+phi_min)	2D/3D indicator

参数	描述	解释
phi_min	最小相位	与电阻率梯度相关
phi_max	最大相位	与电阻率梯度相关
skew	偏斜角	>5 表明存在三维结构
ellipticity	(phi_max-phi_min)/(phi_max+phi_min)	二维/三维结构指示值

When to Use vs Alternatives

适用场景与替代工具对比

Tool	Best For	Limitations
mtpy	Full MT workflow in Python, EDI I/O, visualization, modelling prep	Complex API, evolving between v1 and v2
EMTF	USGS time-series to impedance processing	Fortran-based, processing only
WinGLink	Commercial integrated MT processing and inversion	Expensive commercial license

Use mtpy when you need end-to-end MT analysis in Python: reading EDI files, QC, phase tensor analysis, pseudosections, and preparing data for ModEM or other inversion codes.

Consider alternatives when you need time-series to impedance processing from raw field data (use EMTF), or a fully integrated commercial inversion package with GUI (use WinGLink).

工具	适用场景	局限性
mtpy	Python环境下完整MT工作流、EDI文件读写、可视化、建模准备	API较复杂，v1与v2版本间存在演进变化
EMTF	USGS时序数据转阻抗处理	基于Fortran，仅支持数据处理
WinGLink	商业化集成MT处理与反演工具	商业许可费用高昂

选择mtpy的场景：需要在Python环境中完成端到端MT分析，包括读取EDI文件、质量控制、相位张量分析、拟断面图绘制，以及为ModEM或其他反演代码准备数据。

考虑替代工具的场景：需要从野外原始时序数据转换为阻抗数据（使用EMTF），或需要带GUI的全集成商业化反演包（使用WinGLink）。

Common Workflows

常见工作流

Load, QC, and analyze MT station data

加载、质量控制与分析MT测站数据

Load EDI file(s) with
```
MT()
```
or
```
MTCollection()
```
Inspect station metadata (location, frequency range)
Plot apparent resistivity and phase with
```
PlotMTResponse
```
Check phase tensor parameters for dimensionality (skew > 5 = 3D)
Identify and mask noisy data points using error thresholds
Rotate impedance tensor to geoelectric strike if needed
Create pseudosection for profile data
Export cleaned data for inversion (ModEM format)

使用
```
MT()
```
或
```
MTCollection()
```
加载EDI文件
检查测站元数据（位置、频率范围）
使用
```
PlotMTResponse
```
绘制视电阻率和相位曲线
检查相位张量参数判断结构维数（偏斜角>5=三维结构）
根据误差阈值识别并屏蔽噪声数据点
必要时将阻抗张量旋转到地电走向
为剖面数据创建拟断面图
导出清理后的数据用于反演（ModEM格式）

Common Issues

常见问题

Issue	Solution
No tipper data	Check `mt.has_tipper` before accessing
Bad data points	Use `mt.Z_err / np.abs(mt.Z) > threshold` to mask
Static shift	Apply correction before interpretation
Wrong rotation	Verify coordinate system (N vs E convention)

问题	解决方案
无倾子数据	访问前先检查 `mt.has_tipper`
不良数据点	使用 `mt.Z_err / np.abs(mt.Z) > threshold` 进行屏蔽
静态偏移	解释前先应用校正
旋转方向错误	验证坐标系（北/东约定）

References

参考资料

EDI Format - EDI file structure and sections
Plotting Options - Visualization parameters and styles

EDI格式 - EDI文件结构与章节说明
绘图选项 - 可视化参数与样式

Scripts

脚本

scripts/mt_analysis.py - MT data analysis and QC

scripts/mt_analysis.py - MT数据分析与质量控制脚本