The spin velocity varies with distance from equator. In my latitude of about 50 degrees it is about 1,000 km/sec. At the north pole it is zero.
You can calculate the speed of a certain point rotating with the Earth as an angular velocity multiplied by the distance from the rotation axis to that point.
Nominal mean Earth's angular velocity is 7.292115 x 10 −5 rad · s−1 .
At equator of GRS80 (or WGS84) ellipsoid the nominal speed is about 465 m/s, at poles it is close to 0.
It is not exact because the actual angular velocity and orientation of the rotation axis is slightly changing over time. See International Earth Rotation and Reference Systems Service website (www.iers.org) and IERS Conventions (2010) for details.
Dear Sham Singh, I believe that you are talking about the rotation of the earth about its minor axis. And talking about how fast the earth is moving, from my understanding, it is the speed of rotation of the earth about its minor axis. To determine the speed of rotation of the earth, the circumference of the earth using a particular ellipsoid say WGS 84 ellipsoid has to be computed using its (WGS 84 ellipsoid) semimajor/equatorial radius. Remember that the earth makes one complete rotation in 24 hours.
WGS 84 ellipsoid semimajor axis, a = 6378137.00m.
Circumference of a circle = 2 * pi * R (1)
Where R = Radius of the earth = semimajor axis, a = 6378137.00m
Using equation (1), the circumference of the earth as well as the total distance covers in one complete rotation or in 24 hours can be computed as:
2 * 3.141592654 * 6378137 = 40075016.686m
Note that speed is distance over time. Time here is 24 hours.
Therefore the speed of rotation of the earth about its axis considering the WGS 84 ellipsoid is 40075016.686m/24 hours = 1669792.362m/h or 1669.792km/h. See attached file.
Russian journal publication regarding the question Article Оценка изменений полуосей земного геометрического эллипсоида...
Please look at the animation Data Solid Earth's ellipsoid changes (animation)