COVER: North Fork Toutle River, June 30, 1980. Volcanic mud flow breccia 

and debris from the May 18, 1980 eruption of Mount St. Helens (in upper 

right) are as much as several hundred feet thick in the reach shown. 

Photograph by Austin Post, U.S. Geological Survey. 
Mount St. Helens 

Volcanic-Ash Fall in the 

Bull Run Watershed, Oregon, 

March-june 1980 

By Michael V. Shulters and Daphne G. Clifton 

Hydrologic Effects of the Eruptions 

of Mount St. Helens, Washington, 1980 

GEOLOGICAL SURVEY CIRCULAR 850--A 

1980 
United States Department of the Interior 

JAMES G. WATT, Secretary 

Geological Survey 

Dallas L. Peck, Director 

First printing 1980 

Second printing 1982 

Free on application to Distribution Branch, Text Products Section, 

U. S. Geological Survey, 604 South Pickett Street, Alexandria, VA 22304 
FOREWORD 

On May 18, 1980, after more than a month of earthquakes and eruptions of steam 

and gas, Mount St. Helens, in southwestern Washington, exploded in a volcanic eruption more violent than any in the conterminous United States during the 20th century. 

A lateral blast of hot gas and rock particles devastated an area of about 150 square 

miles on the northern flank of the mountain, knocking down trees to distances as 

great as 12 miles. Within minutes, a giant ash cloud rose to about 60,000 feet. Winds 

then carried the ash eastward across the United States, with heavy deposition occurring in eastern Washington and parts of Idaho and Montana. Other eruptions 

deposited ash in western Washington and parts of Oregon and Canada. 

The hydrologic effects of the May 18 eruption have been both widespread and intense. The explosion caused a massive flow of rock, ice, and mud that devastated the 

upper reaches of the Toutle River on the north and west slopes of the volcano and 

deposited debris in the Toutle River valley for a distance of 17 miles. In the upper 

reaches of the valley the debris deposits are about 600 feet thick. Runoff from the 

melted glaciers and snow, and possible outflow from Spirit Lake, then caused unprece~ented flooding in the Toutle River. The flood transported a massive volume of 

sediment, shattered and uprooted thousands of trees, destroyed most of the local 

bridges, and carried an estimated 25,000 acre feet of sediment into the Cowlitz River. 

A considerable part of this sediment moved through the Lower Cowlitz into the 

Columbia River and formed a shoal that blocked the shipping channel. 

As part of a total Geological Survey effort, Survey hydrologists were speedily on 

the scene collecting data and interpreting the hydrologic effects of the eruptions. The 

major initial hydrologic findings are reported in this circular series. This quick assessment was possible only because the Survey has long conducted extensive waterresources investigations in the affected areas of Washingon, Oregon, and Idaho. 

Hence, there was a well-defined basis for evaluating the types and magnitudes of 

hydrologic changes. 

Geological Survey Circular 850, "Hydrologic Effects of the Eruptions of Mount St. 

Helens, Washington, 1980," consists of individually published short chapters that emphasize data, field observations, and initial comparisons of pre-and post-eruption conditions. Topics in this series will include: observations of the hydrologic events occurring 

on May 18 in the Toutle and Cowlitz Rivers; physical alterations of the Toutle River 

system; the chemical and physical quality of precipitation, streams, and lakes affected 

by volcano-ash fall, ash-leaching studies; and Mount St. Helens glaciers. 

If hi£~ Director 

III 

TABLE OF CONTENTS 

Page 

Foreword___________________________________________________________ III 

Abstract____________________________________________________________ Al 

Introduction --------------------------------------------------------- 1 

Volcanic events ------------------------------------------------------ 4 

Data collection and analysis -------------------------------------------- 6 

Significance of data --------------------------------------------------- 7 

Selected references--------------------------------------------------- 15 

ILLUSTRATIONS 

Page 

FIGURE 1. Photograph showing Mount St. Helens ejecting ash; Mount Hood 

in background -------------------------------------------- A2 

2. Photograph showing Bull Run watershed, looking east toward Bull 

Run Lake and Mount Hood ---------------------------------- 3 

3. Map showing location of Bull Run watershed and its distance from 

Mount St. ~elens ----------------------------------------- 5 

4. Map showing location of sampling sites in Bull Run watershed _______ 6 

5. Bar graph showing precipitation, high-altitude northerly windspeeds, 

and ash-plume elevations, March 27-June 15, 1980 -------------- 8 

6. Scanning-electron-microscope photographs showing volcanic ash 

deposited in Portland, Oreg., on May 25, 1980------------------ 10 

TABLES 

Page 

TABLE 1. Particle-size analyses of volcanic ash ---------------------------- All 

2. Analyses of precipitation, snow, and stream samples from the Bull 

Run watershed ------------------------------------------- 12 

3. Analyses of volcanic ash from the Bull Run watershed and the 

Portland metropolitan area--------------------------------- 14 

v 

Hydrologic Effects of the Eruptions of Mount 

St. Helens, Washington, 1980 

Mount St. Helens Volcanic-Ash Fall 

in the Bull Run Watershed, Oregon, 

March-June 1980 

By Michael V. Shulters and Daphne G. Clifton 

Abstract 

During several periods of volcanic-ash eruption at Mount St. Helens, Wash., 

(March 30, May 25-26, May 30-June 2, and June 12-13, 1980) strong winds from the 

north occurred at high altitudes. As a result, the volcanic ash fell some 50 miles to the 

south in the Bull Run watershed, the principal water-supply source for the 

metropolitan area of Portland, Oreg. 

Water samples collected from three stream sites within-the watershed where compared with samples collected during the same season in previous years. No detectable 

changes were noted in chemical characteristics. 

Precipitation samples collected immediately after the June 12-13 ash fall ranged 

in specific conductance from 20 to 41 micromhos per centimeter at 25°C and in pH 

from 4.0 to 4.3 pH units. Stream samples collected during the May-June period ranged 

in specific conductance from 18 to 28 micromhos per centimeter at 25 oc and in pH 

from 6. 7 to 7.5 pH units. 

Volcanic-ash samples were collected and analyzed for particles size, chemical composition, and weight. Significant differences in particle size of ash were found in 

samples from two separate eruptions. 

Introduction 

On March 27, 1980, Mount St. Helens in southwestern 

Washington began ejecting gas and volcanic ash for the first time in 

more than 100 years. Volcanic activity has continued steadily since 

then. Periodically, gas and ash are ejected from the -volcano. 

Volcanologists have reported that a highly viscous magma is beginning to ooze from the bottom of the mile-deep crater created by an 

explosive eruption on May 18, 1980 (oral commun., D. R. Crandell, 

U.S. Geological Survey, June 27, 1980). (See figure 1.) 

The 102-square-mile (264-square-kilometer) Bull Run watershed 

(fig. 2) is south of the Columbia River, approximately 50 miles (80 

kilometers) south of Mount St. Helens (fig. 3), and supplies water to 

more than 600,000 users in the Portland area. Because of the proximity of the watershed to Mount St. Helens, Portland residents were 

concerned that ash would fall in the Bull Run watershed if a volcanic 

A1 
A2 

FIGURE 1.-Mount St. Helens, Wash., ejecting ash on May 18, 1980. Ash from this eruption drifted eastward, whereas on 

March 30 the ash drifted south toward Mount Hood, Oreg., (shown in background) and the Bull Run watershed. (U.S. 

Geological Survey photograph.) 
Fr<..:URE 2.-Bull Run watershed, looking east toward Bull Run Lake and Mount Hood. (Photograph courtesy of U.S. Forest 

Service.) 

A3 
A4 

eruption occurred during a period of northerly windflow. The first 

such occurrence was on March 30 and resulted in a thin dusting of 

ash over much of the watershed. On April 2, the Water Resources 

Division of the U.S. Geological Survey placed precipitation and ash 

collectors at seven locations in the basin to obtain data on future ash 

falls (fig. 4). These sites were integrated into a hydrologic-data network established earlier in cooperation with the city of Portland for 

an ongoing water-quality investigation of the Bull Run watershed. 

This report presents the data obtained immediately after the 

March 30 ash fall in the Bull Run watershed. Data also are presented 

for the period May 18 through June 15; during this period, ash fall 

was noted on at least three occasions in the Bull Run watershed. No 

data were collected between April 21 and the large eruption on May 

18. Water analyses include temperature, pH, specific conductance, 

acidity, alkalinity, hardness, total dissolved solids, and selected major ions. 

Particle-size analyses, chemical composition, and weight of ash 

collected at selected sites also are shown. 

Volcanic events 

On March 30, gray-black ash and steam from Mount St. Helens 

were ejected to altitudes of 11,000 to 16,000 feet (3,400 to 4,900 

meters) above mean sea level during several eruptions (fig. 5). At 4 

a.m. and 4 p.m., north-northwesterly winds were recorded gusting to 

speeds as high as 100 miles per hour (160 kilometers per hour) at 

altitudes between 10,000 and 20,000 feet (3,000 and 6,000 meters), 

as shown in figure 5. The high-altitude wind measurements were 

taken above Salem, Oreg. U.S. Forest Service aerial observers 

reported at 5:30a.m. that the plume from a 4:11 a.m. ejection had 

traveled about 30 miles (50 kilometers) southeast of Mount St. 

Helens and was drifting toward Mount Hood (figs. 1, 2). At 9:47 

a.m., they also noted that the plume from a 7:03a.m. ejection had 

drifted nearly to Cascade Locks, Oreg. (U.S. Forest Service, written 

commun., April1980). 

Beginning on the morning of May 18, a cataclysmic eruption of 

Mount St. Helens ejected large quantities of ash that covered much 

of eastern Washington, northern Idaho, and western Montana. 

Because winds were generally from the west at that time, detectable 

ash fall in the Bull Run watershed did not occur. A subsequent eruption on May 25, although not as large, was accompanied by highaltitude northerly winds that transported ash into the Bull Run 

watershed and the Portland metropolitan area (fig. 5). Samples collected in the watershed on June 3 show that ash also was deposited 

sometime between May 28 and June 2 although that ash fall was not 

observed in the Portland area. Another ash fall on the Bull Run 

watershed and the Portland metropolitan area occurred on June 12 

and 13, when a large, sustained eruption was accompanied by highaltitude winds from the north. 

FIGURE 3.-Location of the Bull Run watershed and its distance from Mount St. • 

Helens. 
Base from the U. S. Geological Survey 

::>regon and Washington (Shaded relief) 

I : 500,000 ; 1966 0 

A5 

10 MILES 
A6 

EXPLANATION 

e1 Precipitation- and ash<ollector 

sampling site (number is site 

number used in the text) 

.A. Stream-sampling sites 

---- Watershed boundary 

.· 

) 

45 ' 30·- 1 

// 

~~~ 

2 MILES 

Pacific 

Ocean 

\ 

WASHINGTON 

CALIFORNIA 

\ 

"· ::):'Bull Run Lake ·· ...... \ 

) _,.,.....·-........... . /·· 

I DAHO 

NEVADA 

FIGURE 4.- Location of sampling sites in the Bull Run watershed. 

Data collection and analysis 

On April 2, 1980, precipitation and ash collectors were placed at 

the locations shown in figure 2. Each precipitation collector is an 

8-inch (200-millimeter) plastic funnel mounted on a metal post connected to flexible plastic tubing that conveys the precipitation to a 

0.3-gallon (1-liter) sample bottle. Ash collectors are arrays of nine 

open-top bottles with a total catchment area of 48 square inches (310 

square centimeters). Visits to collect samples are made in response 

to -storms and volcanic activity. Ash samples also were collected at 

the U.S. Geological Survey's district office and in other parts of the 

Portland area. 

All field measurements and laboratory procedures for water 

analyses were by methods described by Skougstad and others (1979). 

Water temperatures were determined in the field. Stream and 

precipitation pH values generally were determined by immersing a 

glass electrode in an unstirred subsample of water. Stream samples 

were from a depth-integrated cross-sectional composite. Acidity and 
A7 

specific conductance were determined at the U.S. Geological Survey 

laboratory in Portland, and all other analyses were maoe at the 

Survey's water-quality laboratory in Denver, Colo. The analytical 

results are listed in table 2. 

Ash samples were collected for particle-size analyses at the sites 

listed in table 1. Analytical procedures were those described by Guy 

(1969). Figure 6 shows ash particles deposited in Portland on May 

25, magnified by a scanning-electron microscope. 

Ash from the March 30 eruption was collected at sites 4, 5, and 

7 on April 2 and 4 by removing 1-square-foot (0.09-square meter) 

sections of snow on which the ash had been deposited (table 2). On 

other dates the ash samples were taken from the ash collectors. 

Samples from the Bull Run watershed and the Portland metropolitan 

area were analyzed by the U.S. Geological Survey, Branch of 

Analytical Laboratories, Menlo Park, Calif., and the results are 

given in table 3. 

Significance of data 

Data in this report were collected to document stream and 

precipitation conditions as quickly as possible following ash-fall occurrences in the Bull Run watershed. The Portland Water Bureau 

has collected stream data since 1973 in the North Fork Bull Run 

River, since 1974 in the South Fork Bull Run River, and since 1975 

from Fir Creek. Comparison of the new and historical data suggest 

that no significant changes have occurred in stream water quality. 

This preliminary finding seems reasonable because of the light ash 

fall that occurred in the Bull Run watershed. Unfortunately no 

historical data exist to permit a pre- and post-eruption comparison of 

the chemical characteristics of precipitation. 

In most precipitation samples collected on June 13, the specificconductance values are higher than in any of the previous samples 

and are about equal to or greater than stream conductivities on the 

same day. Nearly all the precipitation collected on this date fell during and immediately following the June 12 ash fall.· Precipitation 

data in table 2 seem to show that pH decreases as specific conductance increases. 

Particle-size data are given in table 1. The data show that for a 

given eruption the particle sizes of the ash samples are similar; 

however, for eruptions on separate days, the particle sizes differ 

significantly. For example, ash from the May 25 eruption at both the 

Bull Run and Portland locations is largely silt (82-89 percent of sample) and ash from the June 12 eruptions at both the Portland and 

Gaston locations is almost equally divided between sand ( 44-48 percent of sample) and silt (46-49 percent of sample). 

Because ash characteristics can vary with different eruptions, 

and because larger accumulations of ash within the watershed remain a possibility, hydrologic-data collection is continuing so that 

any detectable changes that may occur can be documented. 
A8 

~ .4"'1-~~L;'Jn-"l'l-~ll-~l~l-~ll-~ll'l-~ll-"ll'l-"ll-"ll'l-~ll-"l'l'"ll-roll "11-111 

~ 2.0 - ,\'· Daily precipitation, Bull Run -

~ 5}. headworks at site 1 

~ 1.6 - ~:· (Portland Water Bureau) -

~ 1.2- ~ ~~ ~ ., . 

<( .r.: ~ 

-

f- .8- -

; ;[-__ E''·: ll'~~·.l:ill_ __ ~=llima: illt3ziJ~Zl ____ El~-~--_jilli]::::[ .. l__1EJIT·L ----~rm§L _________ Jci 

L.LJ 

L.LJ 

a.. 

(/) 

110-

100-

90-

~ §§ 80 

S:o 

>- ::c 70 __J a: : 

ffi ~ 60 : 

i=~ a: __J 50 §E~ 

~ ~ 40 ::::> 

~ x 30 ~ 

~ 20 

.. . . ' 

.. : .. : ... 

28 30 

MARCH 

Ash fall 

2 4 

a.m. 

I/ p.m. 

Northerly winds 1 0,000 to 20,000 feet -

above mean sea level, Salem 

(National Weather Service) 

Aerial observations of ash eruptions 

at Mount St. Helens 

(U.S. Forest Service) 

-

-

-

-

-

-

-

-

-

-

-

-

-

18 20 22 24 26 28 30 2 4 6 

MAY 

FIGURE 5.- Precipitation, high-altitude northerly wind speeds, and ash-plume elevations, March 28-June 15, 1980. Ash f< 

precipitation samples but the date of the ash fall was not determined. 
A9 

2.4 ""C :::IJ 

2.0 m Daily precipitation, Bull Run (") 

=o 

headworks at site 1 1.6 =i )> (Portland Water Bureau) -l 

5 1.2 z 

.8 z 

z 

.4 (") 

:J: 

m 

4 "' 1 .,. 0 (/) 

~.: -4~: .,\ ... " ..... ~ ..... , .. Northerly winds 1 0,000 to 20,000 feet 110 ...... "''" p.m. :;: :, ">; above mean sea level, Salem 100 :s: 

::. ~·:': (National Weather Service) )> X .. 

'~"'" 

"' <( £,. 

... ~ 90 ~ L ,_ A ..l"' , .. c: .... ~;\.(. < < ' -:5:: .., OC' ~ .. 'f " 

, .. ,. .... 80 ... £,. ........... . .. zz ~,. 1 'I' .., •,. ~ ..... ,.> ~t- ,..., c ,. :s:o (., .... 70 -:::IJ ........ ~ ,. ". '-l a.m. .. < <" .. ... <"' >~ m::r:: L 

""' v'f> .. "., I ~..,c,;<~ C/Jm 

"'"'"'"' >~,.,>I. v 60 ""C:::IJ I., """""'"" j,. A~ I" L., t" mr ....... "' 1 ,. :::IJ-< ,.> ""' 50 I. A C L.,. ,. -./,. ~ .. ..,, ... ,. ' ..... "" .. ..,.,,., :J::E 1 C -1 A ' 0- ... ".._.,. .. 40 c: z ''1 .. " ~ :::IJO ........ "' ., (/) 

30 ""C 

m 

m 

20 _o 

10 

0 :s: . . )> ""'"'"" ' 

·::: ~:~ Aerial observations of ash eruptions 60 X 

.., "' .. .,. ,_ l>-~ cozc: '""'";o. at Mount St. Helens 0--l:s;:: ...... " 50 ~ ~ ~';.:~ (U.S. Forest Service) <::r:: mol> .., ' ....... 40 :s;::c:C/) ""-'~""' ... mC/J::r:: ,., ..... ::1. 

.. ..l.,"' )>l>' 

"""''"" zz""C '. > • 30 o' C/)C/)c: 

mo:S: 

20 l>.,m 

.. r.,m 

10 mm' <mm .. fiJ-i); . . .. .. 0 -l 

5 

8 10 12 14 16 18 20 22 24 26 28 30 2 4 6 8 10 12 14 z 

MAY JUNE 

- ...,.. ______ ,. 

Ash fall Ash fall Ash -fall 

. Run watershed are shown for March 30, May 25-26, and June 12-13. Ash was detected in the May 28-June 2 
AIO 

FIGURE 6.-Scanning-electron-microscope photographs showing volcanic 

ash deposited in Portland, Oreg., on 

May 25, 1980. (Photographs courtesy 

of Nancy G. Temple.) 

100 X ENLARGEMENT 0 

1000 X ENLARGEMENT 

10000 X ENLARGEMENT 

0.5 Millimeter 

0 50 Microns 

0 5 Microns 
All 

TABLE 1.-Particle-size analyses of volcanic-ash fall, Oregon 

[Size determinations by settling-velocity method; ash taken from precipitation collectors] 

Eruption date Percent of ash finer than indicated size in millimeters 

and sample Sand Silt Clay 

identification 0.250 0.175 0.125 0.088 0.062 0.053 0.031 0.016 0.008 0.004 0.002 0.001 

May 25, 1980: 

Bull Run watershed 

(composite sampie from collectors at sites 1-7) __ 100 100 100 99 96 78 38 21 12 7 4 2 

Portland 

(USGS district office) __________ 100 100 100 98 90 83 58 38 17 8 5 2 

June 12, 1980: 

Portland 

(about 1 mile 

northeast of 

USGS district 

office) --------- 100 99 84 61 52 48 34 19 12 6 3 <1 

Gaston 

(about 25 miles 

southeast of Portland) _______ 100 99 89 67 56 53 40 24 13 7 3 2 
A12 

2 

3 

4 

5 

6 

TABLE 2.-Ana/yses of precipitation, snow, and stream samples from the Bull Run watershed, Oregon 

[All chemical analyses are for dissolved constituents. No data were collected between April 21 and May 18. --- indicates not determined] 

0 

~ "0 

0 

-~ 

a. 

0 

a) 

(ii 

"0 

Ol 

.!: 

a. 

E 

(/) "' 

4/2-4/7 

4/7-9 

4/9-11 

4/11-17 

4/17-21 

5/19-28 

5/28-6/3 

6/3-10 

6/10-13 

4/2-7 

4/7-11 

4/11-17 

4/17-21 

5/19-28 

5/28-6/3 

6/3-10 

6/10-13 

4/2-7 

4/7-11 

4/11-17 

4/17-21 

5/19-28 

5/28-6/3 

6/3-10 

6/10-13 

4/2-9 

4/9-11 

4/11-17 

4/17-21 

5/19-28 

5/28-6/3 

6/3-10 

6/10-13 

5/20-30 

5/30-6/3 

6/3-10 

6/10-13 

4/2-9 

4/9-11 

4/11-17 

4/17-21 

5/19-27 

5/27-6/4 

6/4-11 

6/11-13 

4/2-9 

4/9-11 

4/11-17 

4/17-4/21 

5/19-27 

5/27-6/4 

6/4-11 

6/11-13 

7.2 

8.2 

5.6 

11.3 

8.0 

17.8 

12.4 

17.4 

12.0 

.7 

21.2 

14.8 

7.2 

17.2 

12.2 

17.4 

12.0 

.6 

21.4 

15.4 

7.6 

16.4 

15.0 

20.6 

11.5 

9.0 

21.4 

18.6 

6.8 

20.0 

15.0 

21.6 

11.5 

13.8 

18.0 

13.0 

12.0 

19.7 

16.3 

8.1 

11.6 

15.2 

17.0 

12.5 

11.0 

20.1 

20.0 

8.2 

11.8 

17.4 

17.4 

13.5 

5.5 

4.9 

5.0 

4.0 

5.6 

5.0 

4.6 

4.1 

5.2 

4.8 

4.8 

4.3 

5.5 

4.8 

4.1 

4.3 

5.5 

5.0 

4.1 

4.3 

5.4 

4.7 

4.2 

4.1 

5.4 

4.8 

4.1 

4.1 

8 

9 

21 

11 

15 

12 

16 

10 

41 

11 

7 

12 

9 

16 

13 

31 

7 

8 

11 

12 

10 

16 

9 

22 

6 

12 

6 

12 

7 

17 

12 

20 

6 

11 

39 

21 

6 

13 

10 

10 

8 

17 

17 

35 

7 

16 

7 

10 

9 

16 

33 

33 

Q) 

B 

:; 

(/) 

1.1 

1.0 

1.1 

1.3 

.9 

1.3 

1.1 

1.1 

.4 

.4 

.3 

.9 

1.2 

1.2 

.5 

.7 

.8 

.4 

1.3 

.5 

.5 

.6 

1.2 

1.0 

.1 

.3 

.1 

1.5 

.5 

1.1 

1.3 

.7 

.7 

1.8 

.3 

.7 

.9 

.8 

.6 

z 

1/) 

!!. 

Q) 

~ c 

+ 

.!!! 

~ z 

0.05 

.06 

.12 

.17 

.28 

.22 

.05 

.03 

.07 

.09 

.37 

.14 

.06 

.05 

.06 

.10 

.23 

.12 

.04 

.02 

.07 

.12 

.33 

.12 

.01 

.05 

.10 

.04 

.03 

.08 

.18 

.22 

.17 

.05 

.04 

.07 

.18 

.28 

.20 

Q) 

"0 

·;:: 

:J 

0 

u:: 

E 

:J 

·o 

(ij 

(.) 

Precipitation samples 

0.9 0.0 0.1 

.8 .0 .3 

.5 .0 .1 

Milligrams per liter 

E 

:J 

·;n 

Q) 

c 

Ol 

<"0 

:::!!: 

0.0 

.0 

.0 

E 

:J 

·;n 

1/) 

<"0 

0 

a. 

0.2 

.1 

.2 

"' 

~ (/) 

0.1 

.0 

.0 

0 "' (.) 

(.) "' 

1/) 

!!. 

12 

6 

12 

2 

4 

4 

10 

12 

10 

4 

4 

6 

6 

10 

8 

5 

5 

6 

5 

11 

4 

10 

5 

2 

4 

12 

6 

10 

4 

5 

5 

7 

8 

8 

4 

5 

12 

6 

0 

0 

0 

6 

(.) 

<"0 

(.) 

1/) 

!!. 

1/) 

1/) 

Q) 

c 

"0 

:0 

I 

0 

<1 

0 

c 

0 

:; 

0 1/)Q. 

"001 

=> 

OQ) 

0c 

"00 

Q)Q) 

~:J 

0-o 

1/)·-

1/)1/) 

·- Q) 0,!:. 

6 

2 

8 

6.74 

.22 

(2) 

.05 
A13 

TABLE 2.-Ana/yses of precipitation, snow, and stream samples from the Bull Run watershed Oregon- Continued ' 

Milligrams per liter 

(J) 

E 

t'CI 

0 

~ ¥' 

I "C c Q) 

c 0 p O.c -~ Q) 0 0 (.)~ z 6 0 :; Ea> 

:; a. "M Q) C(.) ra- (J) 

0 :5 -~~ t'Cio (.) 0 (.) (.) 0 -on ~ (.) t'CI t'CI U)Q. 0 a) 10 gN Q) t'CI (.) (.) "Ct'CI Q)::: 10 (jj -g@ ~~ ~ (.) (J) (J) => :!:::0 oa> (J)- "C a. 8E § (J) ~ ~ Ulc t'CI(.) 

C)M C) E ~ c E ~ ?: (J) uo 0~ :§_~ .=: .!!! (.)~ + Q) Q) E ·u; -~ ~?: (J) Q)Q) 

c ~~ Q) :2 "C Q) (J) :~ Q) Z::::~ -::I 

a.- a. (jj 2- ~ .!!! 0 "§ ::I c (J) t'CI c ou .Ct:T 

Ea> E 10 U_c 

~ ·u C) t'CI ,g :0 lii "C (J)·- C)Ul 

raa> t'CI :I: ~E ::I ::c 0 lii t'CI 0 "(3 ~ ~ (J)(J) "Q)"-

3: < ·- Q) en .!E.. en a. en~ en z (.) u::: (.) ~ a.. iii ~ :I: o.=:. :::~ 

Snow samples, filtrate 

4 4/4 3 2.2 .003 1.94 

5 4/2 5 3.2 .01 1.29 

7 4/2 3 2.0 .002 3.12 

Stream samples 

North 4/9 4.0 17 1.6 1.2 .0 1.3 .4 .2 6.2 7 5 23 

Fork 4/11 4.6 19 

Bull 4/17 4.8 18 .7 .000 1.1 .0 1.4 .5 .2 7.3 8 6 22 

Run 4/21 4.7 17 

River 5/28 7.8 7.4 22 .3 .002 

6/3 9.0 7.4 23 .7 .000 

616 7.7 7.5 26 

6/10 9.8 7.4 28 .1 .001 

6/13 14.0 7.1 22 1.8 .02 

South 4/9 11.0 18 1.9 .03 1.3 .0 1.5 .5 .2 6.6 7 7 6 19 

Fork 4/11 5.4 20 

Bull 4/17 6.0 20 .5 .000 1.1 .0 1.5 .6 .2 7.8 4 10 6 23 

Run 4/21 5.0 17 

River 5/27 6.4 7.2 21 .7 .005 2 

6/4 14.4 7.0 22 2.1 .003 5 

6111 10.0 7.3- 27 1.3 .01 2 

6/13 14.0 7.2 25 .6 .02 2 

Fir 4/9 9.0 17 1.7 .06 1.6 .0 1.3 .5 .2 6.3 4 5 16 

Creek 4/11 4.2 20 

4/17 4.9 18 .2 .01 1.8 .0 1.4 .6 .2 7.5 6 3 6 22 

4/21 4.0 19 

5/27 5.4 7.2 18 1.6 .01 2 

6/4 9.8 6.8 19 .8 .01 

6/11 8.4 6.7 22 .6 .000 1 

6/13 14.0 7.2 21 .7 .04 2 

'Acidity titrations were carried to an end point pH of 8.3. See American Public Health Association and others (1971) tor additional information. 2 Ash not observed in sample. 
A14 

TABLE 3.-Ana/yses of volcanic ash from the Bull Run watershed and from Portland, Oregon 

[Analyses by P. Klock, c. Heropolus, T. Fries, and S. Neil, Branch of Analytical Laboratories, Menlo Park, Calif., using emission spectroscopy) 

Element 

Aluminum (AI) ___ _ Calcium (Ca) ____ _ 

Iron (Fe) --------- Magnesium (Mg) __ Phosphorus (P) __ _ 

Potassium (K) ___ _ 

Silicon (Si) -------

Sodium (Na) ------

Sulfur (S)2 --------

Titanium (Ti) ____ _ 

Arsenic (As) ------ Barium (Ba) ______ 

Beryllium (Be) ____ 

Boron (B) -------- Cadmium (Cd) ____ 

Chromium (Cr) ____ 

Cobalt (Co) ______ 

Copper(Cu) ______ 

Gallium (Ga) _____ 

Lanthanum (La) ___ 

Lead (Pb) -------- Manganese (Mn) __ Mercury (Hg) _____ 

Nickel (Ni) ------- Scandium (Sc) ____ Strontium (Sr) ____ 

Vanadium (V) _____ 

Ytterbium (Yb) ____ 

Yttrium (Y) -------

Zinc (Zn) --------- Zirconium (Zr) ____ 

Element 

Antimony (Sb) ___ _ Bismuth (Bi) ____ _ 

Cerium (Ce) _____ _ 

Germamum (Ge) __ Gold (Au) _______ _ 

Hafnium (Hf) ____ _ Indium (In) ______ _ Lithium (Li) _____ _ 

Molybdenum (Mo) Niobium (Nb) ___ _ Palladium (Pd) __ _ 

Semiquantitative analyses 1 

Blazed Alder Creek 

(site 5) March 30, 

1980 

Cedar Creek 

(site 7) March 30, 

1980 

Quantitative analyses 1 

Bull Run watershed 

composite sample 

(sites 1. 7) May 25, 

1980 

Southeast Portland 

June 12, 1980 

Percentage of sample, by weight 

(precision is ±50 percent) 

10 

5 

3 

1.5 

.06 

1.5 

>10 

3 

.26 

.7 

10 

5 

5 

1.5 

.06 

1 

>10 

3 

.17 

.7 

9.8 

3.9 

3.9 

1.1 

.09 

1.8 

32 

3.6 

.10 

.46 

(precision is ± 15 percent) 

8.6 

3.5 

3.6 

1.3 

.08 

1.6 

30 

2.7 

.06 

.42 

Parts per million (ppm) of sample, by weight 

(precision is ±50 percent) (precision is ± 5 percent) 

1.5 1.5 3 2 

300 300 410 330 

1.5 1 2.1 1.9 

7 7 17 10 

.3 .1 1 <.2 

15 15 17 13 

15 20 12 12 

30 30 39 38 

20 20 21 18 

20 15 

15 10 20 14 

700 700 570 580 

<1 <1 .05 

15 20 20 15 

15 15 11 11 

500 500 530 420 

70 100 94 89 

1.5 1.5 

15 15 19 15 

50 50 77 57 

100 70 250 140 

Element having concentration, in all samples, below detection limits 

Detection 

limit 

(ppm) 

1 

.2 

50 

7 

.1 

50 

1.5 

100 

.2 

7 

1 

Element 

Platinum (Pt) ____ _ Rhenium (Re) ___ _ Selenium (Se) ___ _ Silver (Ag) ______ _ 

Tantalum~a) ___ _ Tellurium e) ___ _ Thallium I) ____ _ Thorium h) ____ _ Tin (Sn) ________ _ 

Uramum (U)_ ____ _ Wolfram (W) ____ _ 

Detection 

limit 

(ppm) 

5 

7 

10 

.2 

50 

1 

1 

150 

2 

150 

10 

Element 

Antimony (Sb) ___ _ Bismuth (Bi) ____ _ Cerium (Ce) _____ _ Gold (Au) _______ _ 

Lanthanum (La) __ Lithium (Li) _____ _ 

Molybdenum (Mo) 

Detection 

limit 

(ppm) 

1 

.2 

100 

.2 

20 

50 

10 

Element 

Niobium (Nb~---- Rhenium Re ___ _ Selenium ~Se ___ _ Silver (Ag) ______ _ 

Tellurium (Te) ___ _ Tin (Sn) ________ _ 

Wolfram (W)-'----

Detection 

limit 

(ppm) 

25 

50 

5 

1.0 

50 

10 

100 

' Quantitative analyses are performed using a direct reader, which provides better precision than the visual methods used in the semiquantitative test. 2 For sulfur analyses the precision is ± 1 percent using wet chemical methods. 
A15 

Selected references 

American Public Health Association and others, 1971, Standard methods for the examination of water and wastewater (14th ed.): Washington, D.C., American Public 

Health Association, 1,193 p. 

Crandell, D. R., 1980, Recent eruptive history of Mount Hood, Oregon, and potential 

hazards from future eruptions: U.S. Geological Survey Bulletin 1492, 81 p. 

Crandell, D. R., and Mullineaux, D. R., 1978, Potential hazards from future eruptions 

of Mount St. Helens volcano, Washington: U.S. Geological Survey Bulletin 1383-C, 

26 p. 

Guy, H. P., 1969, Laboratory theory and methods for sediment analysis: U.S. 

Geological Survey Techniques of Water-Resources Investigations, book 5, chap. Cl, 

58 p. 

Shulters, M. V., and Clifton, D. G., 1980a, Mount St. Helens ash fall in the Bull Run 

watershed, Oregon, March-April1980: U.S. Geological Survey Open-File Report 

80-740, 9 p. [superseded by U.S. Geological Survey Circular 850-A (this report)]. 

--1980b, Mount St. Helens ash fall in the Bull Run watershed, Oregon, May-June 

1980: U.S. Geological Survey Open-File Report 80-593, 11 p. [superseded by U.S. 

Geological Survey Circular 850-A (this report)]. 

Skougstad, M. W., Fishman, J. J., Friedman, L. C., Erdmann, D. E., and Duncan, S. 

S., eds., 1979, Methods for determination of inorganic substances in water and 

fluvial sediments: U.S. Geological Survey Techniques of Water-Resources Investigations, book 5, chap. Al, 626 p. 

U.S. Geological Survey, 1979, Water resources data for Oregon-Water year 1978: 

Water-Data Report OR-78-1, 650 p.