Table 1. Attributes of the climactic June 15, 1991, eruption, Mount Pinatubo

[MPa, megapascal; Mt, megaton, 10^9 kg; DRE, dense rock equivalent; 
Delta NNO, O2 fugacity relative to nickel-nickel oxide buffer; deg C, 
degrees Celsius] 

------------------------------------------------------------------------ 
      Parameter                    Value                 Basis 
------------------------------------------------------------------------ 
Eruption duration, t(e)         9 hours           Seismic and barograph 
                                                  records(1) 
 
DRE volume erupted magma, V     5 km^3            Studies of eruption  
                                                  deposits and  
                                                  topographic changes(2) 
 
Total SO2 emission, E(SO2)      17 +-2 Mt (min)   TOMS, MLS, and SBUV/2  
                                                  remote sensing(3) 
 
Magma O2 fugacity, f(O2)        10^(-12.1) MPa    Fe-Ti oxides and  
      Delta NNO                 3.2               experimental  
                                                  calibration(4) 
 
Magma temperature, T            780 +-10 deg C    Fe-Ti oxides and 
                                                  experimental  
                                                  calibration(4) 
 
Pre-eruption pressure, P        220 +-50 MPa      Al-content hornblende  
                                                  and experimental phase  
                                                  equilibria(4) 
 
DRE melt volume fraction, f(m)  0.55              Groundmass volume  
                                                  fraction of white  
                                                  pumice by point-count,  
                                                  vesicle-free basis(5) 
 
Melt density, d(m)              2.3 x 10^(12)     Rhyolite glass with 6  
                                   kg/km^3        weight percent  
                                                  water(6) 
 
Dacite density, d(c,m)          2.4 x 10^(12)     Estimated for crystal- 
                                   kg/km^3        glass of dacite,  
                                                  vesicle-free basis(2) 
 
Magma reservoir depth, d        6-11 km           Inversion of  
                                                  seismicity data(7) 
------------------------------------------------------------------------ 
(1)Wolfe and others (this volume). (2)Scott and others (this volume).  
(3)Mean of Bluth and others (1992); Read and others, 1993; and McPeters,  
1993; the uncertainty is the estimated error in the mean (s/n^0.5); 17 Mt 
is a minimum because of potential scavenging by ash, as discussed in text. 
(4)Rutherford and Devine (this volume). (5)This study and Pallister and 
others (1992; this volume). (6)Silver and others (1990). (7)Mori and  
others (this volume).