<P> The memorial has had some unforeseen maintenance issues . In 1984 cracks were detected in the granite and, as a result, two of the panels were temporarily removed in 1986 for study . More cracks were discovered in 2010 . There are many theories about the cause of the cracks, and one often forwarded is that thermal cycling is to blame . In 1990, the Vietnam Veterans Memorial Fund purchased several blank panels to use in case any were ever destroyed . They placed them in storage at Quantico Marine Base . Two of the blank panels were shattered by the 2011 Virginia earthquake . </P> <P> Inscribed in the memorial are the names of service members classified as "declared dead"; as the memorial contains names of individuals that died of circumstances other than killed in action, including murder, vehicle accidents, drowning, heart attack, animal attack, snake bites and others . Also included are the names of those whose status is unknown, which typically means "missing in action" (MIA). The names are inscribed in Optima typeface . Information about rank, unit, and decorations is not given . </P> <P> Those who are declared dead are denoted by a diamond, and those who are status unknown are denoted with a cross . When the death of one who was previously missing is confirmed, a diamond is superimposed over the cross . If the missing were to return alive, which has never occurred to date, the cross is to be circumscribed by a circle . </P> <P> The earliest date of eligibility for a name to be included on the memorial is November 1, 1955, which corresponds to President Eisenhower deploying the Military Assistance Advisory Group to train the Army of the Republic of Vietnam . The last date of eligibility is May 15, 1975, which corresponds to the final day of the Mayaguez incident . There are circumstances that allow for a name to be added to the memorial, but the death must be directly attributed to a wound received within the combat zone while on active duty . In such cases, the determination is made by the Department of Defense . In these cases, the name is added according to the date of injury--not the date of death . The names are listed in chronological order, starting at the apex on panel 1E in July 8, 1959, moving day by day to the end of the eastern wall at panel 70E, which ended on May 25, 1968, starting again at panel 70W at the end of the western wall which completes the list for May 25, 1968, and returning to the apex at panel 1W in 1975 . There are some deaths that predate July 8, 1959 including the death of Richard B. Fitzgibbon Jr. in 1956 . </P>

What names are on the vietnam memorial wall