EOS Volcanology Slide Set #1 SURFACE AND ATMOSPHERIC EFFECTS OF THE 1991 ERUPTION OF MT. PINATUBO, THE PHILIPPINES
Slide set compiled by Pete Mouginis-Mark, University of Hawaii
The impact of volcanoes on the Earth System was dramatically demonstrated in 1991 by the eruption
of Mt. Pinatubo in the Philippines. The June 1991 eruptions of Pinatubo have had near-global
effects on weather and climate via the introduction of sulfur dioxide and aerosols into the
atmosphere. This eruption represents the second largest volcanic eruption this century, second
only to Mt. Katmai (Alaska) in 1912. The materials injected into the stratosphere by Mt. Pinatubo
circled the globe in 3 weeks, and covered about 42% of the Earth's surface in only two months.
Satellite observations made two years after the eruption show that this aerosol layer still
exists, and that many parts of the world experienced a drop in average temperature of
approximately 0.5 degrees C in 1992 compared to the 30-year average. The cold, snowy weather in
New Zealand in late 1992, the severe storm damage caused by hurricanes such as Andrew and Iniki in
the fall of 1992, and the heavy rains in the Midwest of the USA in the summer of 1993 have all
been linked to the atmospheric effects of the eruption of Pinatubo.
This slide set has been compiled in order to provide illustrations of the diverse ways that the
NASA Earth Observing System (EOS) Community is already addressing global change issues through the
analysis of the Pinatubo eruption. Examples are given of ground photographs of the eruption and
the devastating pyroclastic flows and mud flows that were produced, the regional dispersal of the
sulfur dioxide plume as measured by the Total Ozone Mapping Spectrometer (TOMS),
Microwave Limb Sounder (MLS), and Stratospheric Aerosol and Gas Experiment II (SAGE II).
The climate implications are also shown through a comparison of global temperatures for the summers immediately before and after the eruption.
Many of the EOS Interdisciplinary Science (IDS) Volcanology Team's activities focus on
understanding the physics and dynamics of volcanic eruption plumes in the context of climate
change. Eruption plumes provide the direct link between the geology of the volcano, the injection
of material into the stratosphere, and short-term (1 - 3 year) climate change.