watex.methods.DCSounding

class watex.methods.DCSounding(search=45.0, rho0=None, h0=1.0, read_sheets=False, strategy='HMCMC', vesorder=None, typeofop='mean', objective='coverall', keep_params=False, **kws)

Direct-Current Electrical Sounding

A collection of Vertical Electrical Sounding class and computed predictors paramaters accordingly.

The VES is carried out to speculate about the existence of a fracture zone and the layer thicknesses. Commonly, it comes as supplement methods to Electrical Resistivity Profiling after selecting the best conductive zone when survey is made on one-dimensional. Data from each DC-sounding site can be retrieved using:

>>> <object>.site<number>.<:attr:`~.VerticalSounding.<attr>_`

For instance to fetch the DC-sounding data position and the resistivity in depth of the fractured zone for the first site, we use:

>>> <object>.site1.fractured_zone_
>>> <object>.site1.fractured_zone_resistivity_

Parameters:

search: float , list of float

The collection of the depth in meters from which one expects to find a fracture zone outside of pollutions. Indeed, the search parameter is used to speculate about the expected groundwater in the fractured rocks under the average level of water inrush in a specific area. For instance in Bagoue region , the average depth of water inrush is around 45m.So the search can be specified via the water inrush average value.

rho0: float

Value of the starting resistivity model. If None, rho0 should be the half minumm value of the apparent resistivity collected. Units is in Ω.m not log10(Ω.m)

h0: float

Thickness in meter of the first layers in meters.If None, it should be the minimum thickess as possible 1.m .

strategy: str

Type of inversion scheme. The defaut is Hybrid Monte Carlo (HMC) known as HMCMC. Another scheme is Bayesian neural network approach (BNN).

vesorder: int

The index to retrieve the resistivity data of a specific sounding point. Sometimes the sounding data are composed of the different sounding values collected in the same survey area into different Electrical Resistivity Profiling line. For instance:

AB/2

MN/2

SE1

SE2

SE3

…

SEn

Where SE are the electrical sounding data values and n is the number of the sounding points selected. SE1, SE2 and SE3 are three points selected for Vertical Electrical Sounding i.e. 3 sounding points carried out either in the same Electrical Resistivity Profiling or somewhere else. These sounding data are the resistivity data with a specific numbers. Commonly the number are randomly chosen. It does not refer to the expected best fracture zone selected after the prior-interpretation. After transformation via the function vesSelector(), the header of the data should hold the resistivity. For instance, refering to the table above, the data should be:

AB

MN

resistivity

resistivity

resistivity

…

Therefore, the vesorder is used to select the specific resistivity values i.e. select the corresponding sounding number of the Vertical Electrical Sounding expecting to locate the drilling operations or for computation. For esample, `vesorder`=1 should figure out:

AB/2

MN/2

SE2

–>

AB

MN

resistivity

If vesorder is None and the number of sounding curves are more than one, by default the first sounding curve is selected ie rhoaIndex equals to 0

typeofop: str

Type of operation to apply to the resistivity values rhoa of the duplicated spacing points AB. The default operation is mean. Sometimes at the potential electrodes ( MN ),the measurement of AB are collected twice after modifying the distance of MN a bit. At this point, two or many resistivity values are targetted to the same distance AB (AB still remains unchangeable while while MN is changed). So the operation consists whether to the average ( mean ) resistiviy values or to take the median values or to leaveOneOut (i.e. keep one value of resistivity among the different values collected at the same point AB ) at the same spacing AB. Note that for the LeaveOneOut, the selected resistivity value is randomly chosen.

objective: str

Type operation to output. By default, the function outputs the value of pseudo-area in \($ohm.m^2$\). However, for plotting purpose by setting the argument to view, its gives an alternatively outputs of X and Y, recomputed and projected as weel as the X and Y values of the expected fractured zone. Where X is the AB dipole spacing when imaging to the depth and Y is the apparent resistivity computed.

keep_params: bool, default=False,

If True , keeps only the predicted parameters in the summary table, otherwise, returns the usefull details of the site like the depth AB/2 where the DC predicted area parameter is computed.

kws: dict

Additionnal keywords arguments from Vertical Electrical Sounding data operations. See watex.utils.exmath.vesDataOperator() for futher details.

. _Cote d’Ivoire: https://en.wikipedia.org/wiki/Ivory_Coast