The short answer is that eruption or episode duration measures elapsed time from a defined start to a defined end, while a repose interval measures the gap between an end and the next start. An episodic eruption can contain several active durations separated by repose without each episode becoming a separate eruption.
This specialist guide belongs to the Volcanology root. It also connects to The Gold Standard of Education | Learning That Transfers into Life and the How X Works hub. The worked cases are original teaching examples; their values and event logs are stated so each conclusion can be checked.
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Use this guide when a timeline lists three fountain episodes and someone adds the pauses to each episode’s duration, or treats every quiet gap as a new eruption boundary. The worked timelines keep observed surface activity, monitoring evidence, date precision, provisional ends and database conventions separate.
ROUTE 1 · CHAPTERS 1–3
Build the first model
Name the input, state, conversion or predicate before following user-visible results.
ROUTE 2 · CHAPTERS 4–5
Trace the decisive branch
Work the accepted path and the nearest boundary case with original examples.
ROUTE 3 · CHAPTERS 6–8
Change one premise
Rebuild the mechanism when state, value, realm, timing or object kind changes.
ROUTE 4 · CHAPTERS 9–10
Handle limits and failures
Keep abrupt completion, availability and application limits visible.
ROUTE 5 · CHAPTERS 11–12
Verify and explain
Use a decisive fixture, changed-context check and concise final account.
Chapter contents
Build the first model · Chapters 1–3
1. Name the event level before using a clock
Trace the decisive branch · Chapters 4–5
Change one premise · Chapters 6–8
6. Distinguish a pause from an eruption end
Handle limits and failures · Chapters 9–10
Verify and explain · Chapters 11–12
CHAPTER 1 OF 12 · Build the first model
1. Name the event level before using a clock
The short answer is that an eruption can contain episodes, and an episode duration is not automatically the full eruption duration. Chapter 1 focuses on name the event level before using a clock. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. one eruption contains fountain episodes from day1–2, day5–6 and day10–12; their active durations are tracked separately inside the wider eruption. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for name the event level before using a clock is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. declare day5 activity a new eruption and identify which evidence would be needed. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: event hierarchy depends on scientific convention and monitoring context. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. retain eruption ID, episode ID and vent or region. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of name the event level before using a clock should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
The short answer is that duration needs explicit evidence rules for when activity begins and ends. Chapter 2 focuses on define start and end observations. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. episode1 begins with sustained fountaining at 08:00 and ends when surface lava stops at 20:00, giving 12 hours under the stated rule. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for define start and end observations is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. move the start to the first weak spatter at 06:30 and explain the changed definition. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: different products may use different onset criteria. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. save the observation, instrument and confidence attached to each boundary. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of define start and end observations should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
CHAPTER 3 OF 12 · Build the first model
3. Calculate repose from adjacent boundaries
The short answer is that repose is next start minus previous end rather than next end minus previous start. Chapter 3 focuses on calculate repose from adjacent boundaries. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. episode1 ends day2 at 20:00 and episode2 starts day5 at 08:00, producing 60 hours of repose. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for calculate repose from adjacent boundaries is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. delay the second start by six hours and update only the repose interval. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: uncertain ends can make repose a range. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. retain both boundary timestamps before subtraction. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of calculate repose from adjacent boundaries should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
CHAPTER 4 OF 12 · Trace the decisive branch
4. Keep active duration and calendar span separate
The short answer is that the calendar span of an eruption can include quiet intervals that are not active episode duration. Chapter 4 focuses on keep active duration and calendar span separate. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. three episodes last 12, 18 and 30 hours, totalling 60 active hours across an eleven-day calendar span. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for keep active duration and calendar span separate is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. add a four-hour fourth episode inside the same span. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: summing observed active time can miss low-level or unobserved activity. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. publish active-time rules and the full calendar envelope. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of keep active duration and calendar span separate should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
The short answer is that a reproducible timeline gives every episode start, end, duration, following repose and precision. Chapter 5 focuses on work an original episode table. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. episodes A, B and C last 12, 18 and 30 hours; repose A–B is 60 hours and B–C is 78 hours. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for work an original episode table is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. mark B’s end as uncertain by plus or minus three hours and calculate the repose range. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: rounded dates cannot support hour-level precision. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. store raw dates, precision flags and derived intervals. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of work an original episode table should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
The short answer is that a surface pause can occur while monitoring shows the magmatic system remains active within one eruption. Chapter 6 focuses on distinguish a pause from an eruption end. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. lava stops but deformation, tremor and elevated gas persist through a ten-day gap before the same vents resume. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for distinguish a pause from an eruption end is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. remove the monitoring continuity and move activity to a different rift zone. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: no single universal pause threshold resolves every volcano. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. report the convention and volcano-specific evidence. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of distinguish a pause from an eruption end should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
The short answer is that the Global Volcanism Program’s database consistency rule can separate renewed activity after a long pause without turning the threshold into a physical law. Chapter 7 focuses on use the ninety-day convention carefully. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. an 85-day pause stays within one database eruption under the stated convention while a 95-day inactivity gap can initiate a new record. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for use the ninety-day convention carefully is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. change the 95-day case to 89 days and preserve all monitoring evidence. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: exceptions and retrospective revisions can occur. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. distinguish database rule, observatory interpretation and physical process. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of use the ninety-day convention carefully should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
The short answer is that an ongoing or poorly observed event has a censored duration rather than a known final length. Chapter 8 focuses on handle unknown and provisional end dates. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. an eruption started 20 days ago and is still active, so its duration is at least 20 days rather than exactly 20. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for handle unknown and provisional end dates is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. the next report retrospectively dates the last activity three days earlier. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: a provisional end can change with new evidence. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. version the timeline and label open intervals. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of handle unknown and provisional end dates should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
CHAPTER 9 OF 12 · Handle limits and failures
9. Respect date precision in historical records
The short answer is that year-only or month-only boundaries cannot support exact day counts. Chapter 9 focuses on respect date precision in historical records. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. a historical eruption recorded from March to May has a bounded calendar interpretation rather than one precise number of days. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for respect date precision in historical records is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. replace the month-only start with a dated observation on March18. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: absence of reports is not proof of inactivity. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. carry precision and evidence type into every comparison. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of respect date precision in historical records should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
CHAPTER 10 OF 12 · Handle limits and failures
10. Compare volcanoes without threshold bias
The short answer is that counts of episodes and repose depend on monitoring sensitivity and classification rules. Chapter 10 focuses on compare volcanoes without threshold bias. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. a well-instrumented volcano has ten short recorded episodes while a sparsely observed volcano has one broad event record. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for compare volcanoes without threshold bias is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. degrade the first timeline to monthly observations and recount. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: different observation systems can create different apparent event structures. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. compare only records with compatible resolution and rules. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of compare volcanoes without threshold bias should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
The short answer is that the distinction must survive improved sensors and a revised end criterion. Chapter 11 focuses on run a changed-monitoring transfer check. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. adding continuous tremor and gas data reveals low-level continuity across a visually quiet interval, preserving one eruption but keeping the surface repose interval. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for run a changed-monitoring transfer check is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. remove gas data while retaining deformation and state the remaining uncertainty. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: monitoring evidence supports interpretation but does not eliminate all ambiguity. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. show which data stream changes which boundary. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of run a changed-monitoring transfer check should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
The short answer is that a strong note reports event hierarchy, boundary criteria, active durations, repose intervals, open ends, precision and the classification convention. Chapter 12 focuses on write a decision-ready timeline note. Begin with state whether the unit is an eruption or episode, the start and end criteria, timestamp precision, observation gaps, monitoring continuity and the rule for a pause before calculating any duration or repose interval. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. the final fixture states one eruption, three episodes totalling 60 active hours, two repose intervals of 60 and 78 hours and an eleven-day calendar span. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for write a decision-ready timeline note is: what must be defined before this comparison can be made? Separate the population or physical quantity, observation, transformation and conclusion. Two reports can show similar values while using different units, windows, targets or measurement rules.
Now change exactly one premise. replace the final episode with an ongoing event and revise the duration statement. Recalculate from the changed fact rather than editing the old conclusion. Name the earliest quantity or classification that differs, carry that difference through the remaining steps, and state which observations stay comparable.
The main limit is this: the examples do not classify a live volcano or forecast activity. Keep the measured or reported quantity separate from the wider decision, cause or quality claim. A focused example can establish the stated relationship without pretending to settle every operational, clinical, regulatory or institutional question around it.
Practical evidence check. verify observatory reports, timestamps, vents, instruments, confidence and database version. Capture the reported values and exception conditions, and preserve the calculation or observation trail that produced them. A check of only the final label can pass even when an earlier selection, conversion, denominator, target or measurement basis was wrong.
A concise final explanation of write a decision-ready timeline note should state the starting data, governing rule, ordered result and one boundary. It should not depend on one display, one dashboard tile or an unstated assumption. That form is short enough for revision and precise enough for a reproducible evidence note.
Contents · Previous chapter · Return to the Volcanology subject guide
Frequently asked questions
Is every pause the end of an eruption?
No. Short repose can separate episodes within an ongoing eruption, especially when monitoring shows continued elevated magmatic activity.
Why not add repose to episode duration?
They answer different questions. Duration measures active or defined event time; repose measures the intervening gap.
Is ninety days a universal physical law?
No. It is a useful database convention and observational guide, applied with volcano-specific evidence and possible exceptions.
How should an ongoing eruption be reported?
Use an open or right-censored duration such as at least a stated length, with the observation cutoff date.
Continue through the verified reading routes
Start with the wider system
The Gold Standard of Volcanology · The Gold Standard of Education | Learning That Transfers into Life · How X Works hub
Compare the closest mechanisms
Separating Eruption Magnitude from Eruption Intensity · Separating Final Ashfall Thickness from Deposition Rate During an Eruption · Separating Volcanic Tremor Amplitude from Earthquake Magnitude
Choose the next lesson by reader job
Use the subject root to move from this focused mechanism to the next verified question. Follow a specialist link when its preconditions match your code; return to the wider hub when the next task belongs to a different system.
Authoritative sources and evidence checks
USGS Volcano Watch: What is the difference between an eruption and an episode? · USGS Volcano Watch: What defines an eruption pause? · Smithsonian Global Volcanism Program: Eruption database
The USGS and Smithsonian sources establish episode, pause, repose and database-timeline context. Every date, duration, monitoring record and classification result in this guide is an original teaching fixture, not an interpretation or forecast for a live volcano.