Estimates of the weights of pyroclastic material and lava erupted by Parícutin Volcano from early 1943 to early 1952 have given a pyroclastic weight of some 2230 million metric tons and a lava weight of about 1330 million metric tons, making a total of 3560 million metric tons of solids. The weight of pyroclastic material ranged from a maximum daily average of more than 10 million metric tons in the first two weeks of eruption to a minimum of some 65,000 metric tons in 1951. The weight of lava ranged from a maximum daily average of about 650,000 metric tons in 1943 to a minimum of some 170,000 metric tons in the second half of 1950. The only period for which an estimate of the average daily weight of water vapor expelled by the Volcano could be made was the spring of 1945, when some 13,000 metric tons of water were expelled through the crater daily, besides some 500 metric tons contained in the lava extruded concurrently. Since the weight of pyroclastic material and lava erupted by Parícutin in the spring and summer of 1945 is estimated to have averaged about 1.2 million metric tons a day, the water expelled at that time amounted to about 1.1 pct of the total weight of material erupted. If the proportion of water had been nearly constant throughout the active life of the Volcano, the total weight of water would have amounted to some 39 million metric tons.

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Lava emission at Parícutin Volcano came to an abrupt end early on February 25, 1952, just 4 ½ days after the Volcano's ninth anniversary. Explosive activity in the crater declined just as abruptly on the same day and continued only as intermittent, weak, noiseless puffs until March 4, when all activity came to a complete halt. In the 15 months between March, 1952, and June, 1953, when this paper was written, no further activity occurred either in the crater or at the lava vents; and in the opinion of the writers, renewed eruptions are unlikely. During the Volcano's brief final period of activity early in 1952, not only lava and ash eruption, but also explosive activity continued to increase notably over the period previously described [Fries and Gutiérrez, 1952b]. The trend toward increased activity had already been well established in the second half of 1951 [Fries and Gutiérrez, 1952b, p. 725], when the earlier continuous decline in activity was first definitely interrupted. Rainfall for the year 1952 was also greater than that of the year before, although this increase had no close relationship to the activity of the Volcano. The cessation of all activity on March 4 provided the opportunity to check the relationship of rainfall to intensity of activity and also the validity of the ashfall records of previous years.