What kind of characteristics does the Great Tribulation have in LDS eschatology? There is this other question with an answer that touches on the Great Tribulation as it is viewed in LDS eschatology, but I would like to ask more specifically about the situation on earth during the Great Tribulation:


What physical events do Mormons believe will happen before or during
the Great Tribulation?
In what sense will it be a "Great Tribulation" - is this mostly
symbolic or are there spiritual or physical (e.g. economical)
reasons that warrant the label "Great Tribulation"?
Do Mormons have any official beliefs on how long the Great
Tribulation is expected to last?
Before I begin I'd like to restate from the other answer that the phrase "Great Tribulation" is not used in Mormon terminology/teachings and LDS teachings most closely align with post-tribulationist. That is Mormon's believe in a chronology that is along the lines of tribulation, second coming, Millenium, and then the last judgement. I will not go into great detail as most of this is covered in LDS manuals and covers several chapters, feel free to look at the referenced manuals if you want more detail.


  
  What physical events do Mormons believe will happen before or during the Great Tribulation?
  


Signs of the Second coming1


Wickedness, War, and Turmoil-being fulfilled
The Restoration of the Gospel-fulfilled
The Coming Forth of the Book of Mormon-fulfilled
The Gospel Preached to All the World-partly being fulfilled
The Coming of Elijah-fulfilled
Lehi's Descendants Will Become a Great People-partly being fulfilled
Building of the New Jerusalem
Other signs (see the scripture references at the bottom of the chapter if you want the others)


Second Coming2


Jesus will cleanse the earth-wicked will be destroyed
He will judge His people
He will usher in the Millenium
He will complete the First Resurrection
He will take His rightful place as King of heaven and earth


Millenium3


Temple/Missionary work
Satan bound
Peace on earth
Righteous government
No death
All things revealed
A final struggle at the end of Millenium when Satan will be set free for a short time. Satan will gather his armies and they will be cast out forever.


Final Judgement4


Judged by words, works, and thoughts
Judged by records
Inheriting a place in a Kingdom of Glory



  
  In what sense will it be a "Great Tribulation" - is this mostly symbolic or are there spiritual or physical (e.g. economical) reasons that warrant the label "Great Tribulation"?
  


Because this isn't Mormon terminology it is hard to get a specific answer but based on the previous answer (above) there are spiritual and physical reasons that would warrant the label "Great Tribulation".


  
  Do Mormons have any official beliefs on how long the Great Tribulation is expected to last?
  


No. We have to measure when the first sign of the Jesus' Second Coming is to the Second coming (no specific time period), plus 1,000 year Millenium, and then Final Judgement (again no specific time period). So at least 1,000 years.

1 https://www.lds.org/manual/gospel-principles/chapter-43-signs-of-the-second-coming?lang=eng

2 https://www.lds.org/manual/gospel-principles/chapter-44-the-second-coming-of-jesus-christ?lang=eng

3 https://www.lds.org/manual/gospel-principles/chapter-45-the-millennium?lang=eng

4 https://www.lds.org/manual/gospel-principles/chapter-46-the-final-judgment?lang=eng