Once you have your wiring done you will want to know the numerical range of your Memsic sensor in order to give your program the correct numbers to look for when the board is shaken.
Anything over that will indicate movement.
Once you have your baseline numbers you can use them to program the logic to let your seismometer know when to sound off. The following Blocklyprop program is what I wrote for my seismometer but you can make your own noises and OLED graphics to suit yourself. It is easy to modify and there are many things you can do with the OLED! Be sure to replace my Memsic baseline numbers with your own.
The logic I used for the seismometer is: if the numbers coming from the Memsic sensor are greater than the numbers when it is in its steady state it will sound the alarm. I put the speaker and the OLED in their own functions to make it easy to change them when the whim hits me for something different or better. Do not forget to right click on a block and use the help function to get the information on a block and how to use it. I hope you enjoy this project!
Links
[1] https://learn.parallax.com/sites/default/files/content/AB-Blockly/Projects/Seismometer/Seismometer-Project.zip