Strike one for the conspiritards; earthquake grid locations caused by rounding errors.
https://www.volcanodiscovery.com/earthquakes/faq/why-quakes-are-along-grid.html
Why seem quake epicenters sometimes distributed along some sort of grid?
Recent quakes under La Palma Island (Oct 2021), using data from EMSC, apparently aligned on grid caused by rounding of lat/lon values to the second digit after comma, approx. 500-1000 m resolution (image: EMSC)
Sometimes, when you zoom in a lot on maps showing earthquake epicenters, the locations are arranged on parallel N-S / E-W grid lines.
This is an artifact caused when the calculated locations of quakes are rounded to the closest decimal after the comma, whose value is still larger than the error span of the measurement and not to suggest a wrong level of accuracy that simply cannot be achieved.
Example: A fictive quake's true epicenter is 35.35768962 N / 25.93617482 E. Now, let's assume that the accuracy of possible detection by instruments is maximum 0.01 deg latitude or longitude. The complex numerical seismic calculations might give the following raw result:
35.350108457… N / 25.94016237809.. While this might seem extremely accurate, it is not. Even though numerically produced data values have as many digits as the number of bits in computers allow, the accuracy is far less and only as good as input data.
The results are thus within 0.01 deg error (or 1 km) margin from their unknown true value. Most agencies will round the results to a value that reflects the accuracy by the value of the last digit.
In this case, the quake's epicenter might be published as 35.35 / 25.94
If there are many quakes in an area where the quakes are closer together than the maximum resolution of the lat/lon calculations, it will appear that many quakes end up having the same rounded latitude or longitude value, and thus, seemingly are arranged on a grid corresponding to these rounded values.
In reality, the quakes are of course not aligned on this grid, but at their true locations, which is not exactly known.