332:
275:
389:
218:
190:
Field-Trip Guide to Mount St. Helens, Washington—An
Overview of the Eruptive History and Petrology, Tephra Deposits, 1980 Pyroclastic Density Current Deposits, and the Crater
64:
188:
Pallister, John S.; Clynne, Michael A.; Wright, Heather M.; Van Eaton, Alexa R.; Vallance, James W.; Sherrod, David R.; Kokelaar, B. Peter (2017). "Eruptive
History".
373:
474:
454:
316:
499:
430:
259:
504:
449:
193:
459:
366:
479:
359:
309:
509:
423:
252:
131:, having taken place in possibly 1860 BCE as part of the Smith Creek eruptive period. The tephra consists of
302:
42:
494:
484:
96:
464:
416:
245:
489:
469:
339:
163:
158:
168:
8:
282:
116:
57:
197:
404:
347:
290:
233:
128:
120:
47:
27:
400:
343:
286:
229:
443:
201:
79:
66:
331:
274:
225:
388:
396:
124:
217:
135:
132:
112:
187:
127:. It was created by the largest known volcanic eruption from
115:deposit that covers portions of the U.S. state of
441:
281:This article about a location in the state of
424:
367:
310:
253:
431:
417:
374:
360:
317:
303:
260:
246:
194:United States Department of the Interior
475:Volcanic eruptions in the United States
455:Geologic formations of British Columbia
442:
383:
326:
269:
212:
153:
151:
13:
500:Washington (state) geography stubs
14:
521:
338:This article about a location in
148:
505:British Columbia geography stubs
387:
330:
273:
216:
450:Volcanism of Washington (state)
460:Geologic formations of Alberta
181:
119:and the Canadian provinces of
1:
141:
403:. You can help Knowledge by
346:. You can help Knowledge by
289:. You can help Knowledge by
232:. You can help Knowledge by
7:
480:Prehistoric volcanic events
10:
526:
382:
325:
268:
211:
80:46.1912000°N 122.1944000°W
111:is a geologically recent
95:
53:
41:
33:
23:
18:
340:British Columbia, Canada
164:Global Volcanism Program
85:46.1912000; -122.1944000
510:Alberta geography stubs
169:Smithsonian Institution
399:location article is a
76: /
19:Yn tephra eruption
495:Volcanology stubs
485:Plinian eruptions
412:
411:
355:
354:
298:
297:
241:
240:
105:
104:
517:
465:Mount St. Helens
433:
426:
419:
391:
384:
376:
369:
362:
334:
327:
319:
312:
305:
277:
270:
262:
255:
248:
220:
213:
206:
205:
185:
179:
178:
176:
175:
155:
129:Mount St. Helens
121:British Columbia
91:
90:
88:
87:
86:
81:
77:
74:
73:
72:
69:
28:Mount St. Helens
16:
15:
525:
524:
520:
519:
518:
516:
515:
514:
490:Tephra deposits
470:VEI-6 eruptions
440:
439:
438:
437:
381:
380:
324:
323:
267:
266:
210:
209:
186:
182:
173:
171:
157:
156:
149:
144:
84:
82:
78:
75:
70:
67:
65:
63:
62:
61:
60:, United States
12:
11:
5:
523:
513:
512:
507:
502:
497:
492:
487:
482:
477:
472:
467:
462:
457:
452:
436:
435:
428:
421:
413:
410:
409:
392:
379:
378:
371:
364:
356:
353:
352:
335:
322:
321:
314:
307:
299:
296:
295:
278:
265:
264:
257:
250:
242:
239:
238:
221:
208:
207:
196:. p. 11.
180:
146:
145:
143:
140:
103:
102:
99:
93:
92:
55:
51:
50:
45:
39:
38:
35:
31:
30:
25:
21:
20:
9:
6:
4:
3:
2:
522:
511:
508:
506:
503:
501:
498:
496:
493:
491:
488:
486:
483:
481:
478:
476:
473:
471:
468:
466:
463:
461:
458:
456:
453:
451:
448:
447:
445:
434:
429:
427:
422:
420:
415:
414:
408:
406:
402:
398:
393:
390:
386:
385:
377:
372:
370:
365:
363:
358:
357:
351:
349:
345:
341:
336:
333:
329:
328:
320:
315:
313:
308:
306:
301:
300:
294:
292:
288:
284:
279:
276:
272:
271:
263:
258:
256:
251:
249:
244:
243:
237:
235:
231:
228:article is a
227:
222:
219:
215:
214:
203:
199:
195:
191:
184:
170:
166:
165:
160:
154:
152:
147:
139:
137:
134:
130:
126:
122:
118:
114:
110:
100:
98:
94:
89:
59:
56:
52:
49:
46:
44:
40:
36:
32:
29:
26:
22:
17:
405:expanding it
394:
348:expanding it
337:
291:expanding it
280:
234:expanding it
223:
189:
183:
172:. Retrieved
162:
159:"St. Helens"
108:
106:
37:1860 BCE (?)
226:volcanology
83: /
71:122°11′40″W
444:Categories
283:Washington
174:2020-01-28
142:References
117:Washington
68:46°11′28″N
58:Washington
202:2328-0328
133:pumiceous
109:Yn tephra
54:Location
397:Alberta
125:Alberta
48:Plinian
24:Volcano
200:
136:dacite
113:tephra
395:This
342:is a
285:is a
224:This
401:stub
344:stub
287:stub
230:stub
198:ISSN
123:and
107:The
43:Type
34:Date
97:VEI
446::
192:.
167:.
161:.
150:^
138:.
432:e
425:t
418:v
407:.
375:e
368:t
361:v
350:.
318:e
311:t
304:v
293:.
261:e
254:t
247:v
236:.
204:.
177:.
101:6
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
