[Dave Lev (OP)]

In the following Article it is stated the Earth heat is due to radioactivity:
https://theconversation.com/where-does-the-earths-heat-come-from-151788
"The average heat flow from the earth?s surface is 87mW/m2 ? that is, 1/10,000th of the energy received from the sun, meaning the earth emits a total of 47 terawatts, the equivalent of several thousand nuclear power plants. The source of the earth's heat has long remained a mystery, but we now know that most of it is the result of radioactivity."

That radioactivity emits neutrinos that are called "geoneutrinos":
"There are various kinds of radioactivity, each involving the spontaneous release of particles and emitting energy that can be detected in the form of heat deposits. Here, we will be talking about ?beta? decay, where an election and a neutrino are emitted."
"These kinds of particles are called geoneutrinos, "
In order to meet the Earth heat 10^25 geoneutrinos must be emitted per second:
"According to standardized measures, one megaelectronvolt is equivalent to 1.6 10^-13 joules, so it would take around 10^25 decays per second to reach the earth's total heat."
They ask the following question:
"The question is, can these neutrinos be detected?"

However, we know that the sun also generates neutrinos
https://en.wikipedia.org/wiki/Solar_neutrino

"A solar neutrino is a neutrino originating from nuclear fusion in the Sun's core, and is the most common type of neutrino passing through any source observed on Earth at any particular moment"

Therefore, would you kindly answer the following:

1. What is the difference between the Sun Fusion neutrinos to the Earth radioactivity neutrinos that are called "geoneutrinos"?

2. Why the neutrinos detectors on Earth can only detect the Sun Fusion neutrinos and not the "geoneutrinos" that are created on Earth?

[Origin]

1. What is the difference between the Sun Fusion neutrinos to the Earth radioactivity neutrinos that are called "geoneutrinos"?

One is created in the earth and the other is created in the sun.

2. Why the neutrinos detectors on Earth can only detect the Sun Fusion neutrinos and not the "geoneutrinos" that are created on Earth?

Because the sun creates 10^13 more neutrinos per second than the earth, according to your source.
I would think the detectors can see geoneutrinos but would detect much less than solar neutrinos. 

Edit:
I just noticed that you assumed each decay emits a neutrino which is not true, it depends on the type of decay.  That would mean the that the difference between the sun and the earth is much more than 10^13 neutrinos.
Edit:
Just checked and 10^25 is a good number.

[Kryptid]

This thread had better not become one about nuclear fusion denialism.

2. Why the neutrinos detectors on Earth can only detect the Sun Fusion neutrinos and not the "geoneutrinos" that are created on Earth?

They can be detected. The link you posted said so:

KamLAND has announced more than 100 events and Borexino around 20 that could be attributed to geoneutrinos, with an uncertainty factor of 20-30%. We cannot pinpoint their source, but this overall measurement ? while fairly rough ? is in line with the predictions of the simulations, within the limits of the low statistics obtained.

[Origin]

This thread had better not become one about nuclear fusion denialism.

I would bet that it is going to go there eventually...  Dave is pretty predictable.

[paul cotter]

It should also be noted that neutrinos are very difficult to detect as they hardly react with matter at all(low cross section is the correct term, I believe). Given that the sun emits vastly more neutrinos than the earth it is going to be next to impossible to detect neutrinos from the earth.