The Ms  5.8 Bob–Tangol earthquake strikes Kerman Province in Iran, destroying villages and killing 665 people.

The 1977 Bob–Tangol earthquake struck Kerman province of Iran on December 20, 1977, at 03:04 Iran Standard Time. The earthquake measured M_w 5.9 and struck at a depth of 22.7 km (14.1 mi). A maximum Modified Mercalli intensity of VII was evaluated based on damage. It had a strike-slip focal mechanism, which was unusual as the source structure was a thrust fault. It was part of a sequence of strong earthquakes along the 400 km (250 mi) Kuh Banan Fault. Between 584 and 665 people perished while a further 500–1,000 were injured; thousands were also made homeless. Casualties from the earthquake was considered moderate due to the sparsely populated area it affected. Preceded by foreshocks the month before, many residents became wary of a larger earthquake and took refuge outside their homes, contributing to the moderate death toll. However, there were none immediately before the mainshock so many were still in their homes when it struck. Aftershocks were felt for several months, some causing additional damage.

December 19 is the 353rd day of the year in the Gregorian calendar; 12 days remain until the end of the year.