Tutorial: Processing gravity data with Harmonica

Santiago Soler, Andrea Balza Morales and Agustina Pesce

BEFORE THE TUTORIAL:

ABSTRACT

1. Load the gravity dataset.
2. Compute gravity disturbance by removing the normal gravity through Boule.
3. Project** the data to plain coordinates.
4. Load the survey area's digital elevation model (DEM).
5. Compute Bouguer gravity disturbance by forward modeling the topography with prisms.
6. Interpolate the Bouguer gravity disturbance onto a regular grid at a constant height through the equivalent layer technique.
7. Obtain the Bouguer gravity disturbance on a profile using the same equivalent layer.

TIMESTAMPS
00:00 Matt's intro
01:10 Tutorial introduction
02:11 Setup your system
05:34 What is Harmonica?
07:16 Roadmap
10:37 Import packages
13:13 Download the gravity dataset
22:11 Project the data into plain coordinates
27:55 Understanding the data
29:39 Compute gravity disturbance
38:19 Compute Bouguer gravity disturbance (model the topography with prisms)
01:07:48 Compute residuals (remove regional trend)
01:14:45 Grid the residuals with equivalent sources (a.k.a. equivalent layer)
01:34:00 Extract a profile
01:43:21 Saving results as open-format files
01:45:39 Wrap up

IMPORTANT
Please note that this tutorial was created with the following dependencies:
dependencies:
- python==3.8.*
- numpy
- pandas
- xarray
- matplotlib
- jupyterlab
- proj
- pyproj
- netcdf4
# Fatiando a Terra libraries
- pooch
- verde
- boule==0.2.0
- harmonica==0.2.1

Over time the syntax could change. Check the repository for notices, more information, and more recent versions.

[geoexplorationltd]

Fantastic - Really nice. Where we can found basic code?

[JoelPDlima]

Hi,
I’m facing an AttributeError while working with the harmonica module in Python. The error message shows that the module doesn’t have an attribute named 'EQLHarmonic'.

AttributeError Traceback (most recent call last)
Cell In[35], line 1
----> 1 eql = hm.EQLHarmonic(damping=100, relative_depth=5e3)

AttributeError: module 'harmonica' has no attribute 'EQLHarmonic'

Is it possible that there may be a typo in the attribute name?

[JoelPDlima]

Hi,
Now, I'm facing another issue with this part:
grid = eql.grid(
coordinates,
upward=2200,
region=region_deg,
spacing=0.01,
dims=("latitude, longitude"),
data_names=["bouguer_disturbance"],
projection=projection,
)
grid

It seems, some fuction has been changed...

ValueError: The 'upward', 'region', 'shape' and 'spacing' arguments have been deprecated. Please pass the coordinates of the target grid through the 'coordinates' argument.

[inves]

I have STRM DEM and how I use this dem data to calculate de residual gravity

[juanacosta]

Hey, Can you recommend me a method to obtain Edge-Boundary detection of anomalies as well as Euler Deconvolution For most of the methods in internete I need an area-square-bound, and I have a similar data as Thanks

[rezayee]

Hi man
Good afternoon
I have one more question, but one is more important.
1- how to install and activate a harmonica environment in an anaconda?