A spectacular fireball was observed crossing Northern Italy from SE to
NW on 19 January 1993, at about 00.33 h UT, ending with an explosion
approximately over the city of Lugo di Romagna. Calculations on the fr
agmentation of the body were performed for an entry velocity of 25 km
s-1, a low-inclination of about 14-15-degrees, and a material strength
S = 10-50 MPa (Bronshten, V. A., Physics of Meteoric Phenomena. Reide
l, 1983) valid for stony (and carbonaceous) chondrites, with heights o
f first fragmentation h(break) less-than-or-equal-to 35-40 km. For est
imated visual magnitudes M(upsilon) = -22 to -25 at the peak of the li
ght-curve corresponding to values of an initial radius of 1.5-3 m (Hil
ls, J. K. and Goda, M. P., Astron. J. 105, 1114-1144, 1993), a meteor
luminosity ranging between 300 and 4000 GW is obtained, consistent wit
h the radiant flux values obtained by the Stefan-Boltzmann law for a b
lack-body temperature of tens of thousands degrees. The explosion of t
he bolide produced low-frequency (1.5-2 Hz) infrasonic waves which wer
e monitored by a microseismic network of three stations near Ferrara a
nd by regional seismic stations of the ING (Istituto Nazionale di Geof
isca) at 20-60 km horizontal distances from the epicentre located in t
he stratosphere. Microanalysis of recovered particles in the explosion
zone, in the form of spherules of vaporized and recondensed material,
reveals the relative importance of light chemical elements typical of
soft structures.