You appear to have been using the maximum zoom available to you which adds to your problems ... then assuming that you buy a tripod it is quite likely that with a 15 second exposure it will still be blurred ... a] due to an innitial rocking of the camera on pressing the trigger b] a cheap tripod can be less steady than hand holding unless it is a mini-tripod c] for your comfort you extended the centre column ... a tripod can be steady so long as you do not turn it into a pole/ monopod by raising the column. d] it was wi ndy and the wind disturbed your rig e) you kept hold of the camera during the exposure.
Unfortunately a lot of traps even if you follow advice and buy a tripod

And in this kind of situation and many more when using a tripod I use the ten second release and having pressed the trigger I leave the camera and tripod untouched during the countdown.
Some people when it is windy hang a heavy weight from the underneath of the tripod ... rocks in your camera bag ?
If you can get closer to the subject it could help if you used the wide end of your zoom.
Nearly forgot because I shoot MFT without a mirror but that for time exposures of any length you consider raising the mirror prior to shooting rather than have it lift out of the way as you press the trigger ... others will advise you of the finer points of this as I have never had the facility ... just know careful people do this
So I hope you take note of these traps and your next shot comes out as you want it ... have fun !
edit .. I am suprised that nobody has told you it is against CiC rules to post somebody else's photo ... you should link to it
find the photo .. copy the URL [CTRL+C] and in the middle block of options here at CiC the first icon of the third block brings up a menu for you to post while you have a word or phrase highlighted ... that then becomes the link to the photo. [CTRL+V enters what you have copied]
Sorry if you already know all this
