Activity of Parícutin volcano from December 1, 1946 to March 31, 1947 patterns
A record of the activity of Parícutin Volcano, Michoacán, Mexico, is shown in the diagram of eruptive characteristics, Figure 1, covering the period December 31, 1946 to March 31, 1947, and is supplemented by the maps of the areal extent of the lava flows, Figures 2 and 3. This continues the previous record for the period from September 18 to November 30, 1946 [Trans. Amer. Geophys. Union, v. 28, no. 4, pp. 567–572, 1947], and reference is made to that report for explanatory discussion of the diagram of eruptive characteristics and for general information concerning the methods of investigation. As shown in Figure 1, the periods of predominantly heavy pyroclastic eruption occurred December 16 to February 14 and March 15 to 28. The periods of greater effusion of lava occurred December 1 to 20 and January 22 to February 25.