What is the different bewteen ucsc simple repeat and tandem repeat

Question

[octpus616]

Hi

I noticed that UCSC has released various masks and annotations for the human reference genome, among which simple repeats and tandem repeats seem to be confusing. In UCSC, you can find these two annotation files respectively. For example, you can find them at the following locations in hg38.

https://hgdownload.soe.ucsc.edu/goldenPath/hg38/database/simpleRepeat.txt.gz
https://hgdownload.soe.ucsc.edu/goldenPath/hg38/bigZips/hg38.trf.bed.gz

I noticed that the contents of these two files are actually different, but some literatures directly use simple repeat as the annotation for TRF, including some pages of UCSC[1], and there is any complete differentiation between the two?

1. USCS web page about simple repeat (and try?): https://genome.ucsc.edu/cgi-bin/hgTables?db=hg38&hgta_group=rep&hgta_track=simpleRepeat&hgta_table=simpleRepeat&hgta_doSchema=describe+table+schema