The World Organization of Volcano Observatories (WOVO) seeks to build WOVOdat, a modern database of worldwide volcanic unrest.
The term, volcanic
unrest mean significant changes (usually but not always increases) in
seismicity, ground deformation, gas composition, fumarolic activity, or other
parameters, within or adjacent to a volcanic system between and in the early
stages of eruptions. Data from observatories
around the world will be brought for the first time into common formats and Web
accessibility. Data will be
geospatially and time-referenced, to provide 4-D pictures of how volcanic
systems respond to magma intrusion, regional strain and other disturbances, and
as they prepare to erupt.
The WOVOdat database will be the central
resource of a system to link to other databases such as that of IRIS (global
waveforms), UNAVCO (global GPS coordinates and strain vectors) and the
Smithsonian’s Global Volcanism Program (historical eruptions). WOVOdat will serve volcanologists and other
earth scientists as epidemiological databases serve the medical community. It will support searches for subtle,
previously unrecognized patterns of unrest, research into the processes of
volcanic unrest and improvements in eruption forecasts.
A summary of initial planning (Phase-I) may be
found at http://www.wovo.org/WOVOdat/plansum.htm. Work in Phase-II, design, and Phase-III,
pilot testing, will follow promising new directions in defining and
categorizing volcano data (tentatively using XML and a modern relational
database engine), for integrating data from multiple sources, each of which has
its own instrument characteristics, data formats, and local data reduction
methods. Sample data input methods and
sample output views using data from several cooperating observatories will be
used in the design and testing.
Phase-IV, populating the database, and Phase-V, maintenance and
enhancements, will take place in separate follow-on project handled primarily
by WOVO observatories.
Volcanoes
exhibit a complex suite of geophysical, geochemical, geologic, and hydrologic
changes (unrest) as magma ascends and
prepares to erupt. For example, small
earthquakes will mark where magma pressures are fracturing the rock through
which magma will rise. Slight swelling
of the ground surface will also reflect increased magma pressure. Gases that were soluble under higher
pressures while magma was at depth exsolve and escape through fumaroles as
magma rises and confining pressures decrease.
Additional unrest may occur even without magma ascent, reflecting either
in-situ changes of the magma or interaction between magma, hydrothermal systems
and regional tectonic stress. Although
volcanic unrest can at times bewilder and lead to false alarms, it also offers
a window into the volcanic subsurface and the potential to forecast eruptions.
Increasingly, as
populations on volcanic slopes expand and observatory experience and
technologies improve, the public expects that both the accuracy and precision
of eruption forecasts will rise.
Volcanologists must now monitor the wide range of parameters and changes
noted above, and project and interpret trends in the data. Eruption forecasts -- both empirical and
process-oriented -- are based on comparing current unrest with that of prior
unrest and its outcomes.
A large and valuable
body of data has been acquired over the past century. Potentially this could be studied in the same way that
epidemiologists study the occurrence, symptoms, and origins of disease. A whole new field of volcano epidemiology awaits, and we anticipate that it will
significantly improve eruption forecasts as well as address a variety of
research questions.
The data of volcanic
unrest are currently so widely scattered that they are largely inaccessible
except through the published literature -- usually only summaries - and direct
queries to those who collected the data.
Data files exist only in individual observatories and with individual
researchers. There is no centralized,
standardized database. This fragmented
state of affairs utterly fails to take advantage of the intellectual power of
worldwide observatory experience and of galloping information
technologies. There is no way at
present to search through that collective experience for close matches or for
subtle but instructive patterns or to test hypotheses about unrest at a large
number of volcanoes.
We
propose to remedy this anachronism by building a modern database of worldwide
volcanic unrest. Because most data on
such changes would come from members of the World Organization of Volcano
Observatories (WOVO), and many of the users would be from the same
observatories, we propose that this new database of volcanic unrest be called
WOVOdat. However, WOVOdat will have a
Web interface and be open to all. We
anticipate wide usage for academic research and teaching as well.
The principal uses of
WOVOdat would be:
·
Research on magmatic ascent, vesiculation,
degassing and other processes that control volcanism as manifested in changes
that are monitored by volcano observatories.
·
Reference by volcanologists who must forecast
the outcome of unrest and need to know of similar unrest elsewhere, its causes
and outcomes.
·
Research on regional strain events as seen at
sensitive, metastable volcanic systems.
A number of recent observations, e.g., following the 1992 Landers
earthquake (Hill et. al., 1993), point to greater sensitivity and participation
of volcanic systems than previously believed.
·
Reference by risk analysis professionals and the
insurance industry.
·
Data source for K-12 and university
students. Volcanoes capture student
interest and are wonderful vehicles for teaching basic science concepts and
lessons about inquiry in complex systems.
Learning about the volcanoes is a bonus.
·
Reference for the general public. Well beyond the student years there is
strong public interest in volcanism as a vivid reminder of the forces of
nature, and the Web surely encourages this.
Some also want to know more about volcanoes in their backyard.
·
A resource for researchers from outside the
geosciences, e.g. those improving techniques for data mining or studying the
general phenomenon of self-organized criticality.
An
added benefit, though not a use per se,
is that adoption of common data formats and data entry protocols will
facilitate exchange/interchangeability of monitoring instruments, data, and
data processing tools.
Sidebar:
The
value of historical experience on volcanoes: Many languages and
cultures of the world emphasize the value of remembering history. In geodynamics the past and present are the
key to the future. At volcanoes that
have not erupted for many years we must extend our view of the past to other,
similar volcanoes around the world. For
example, at Mount St. Helens in 1980 volcanologists readily saw that the
volcano was restless, that the north flank of the volcano was unstable and that
a large landslide was possible. What
was not so clear was that the hydrothermal system was probably pressurized and
that, as a result, a complex interplay between hydrothermal pressures, steam
explosions, over-steepening, and gravity could lead to a giant landslide and
blast at any moment without the usual acceleration of creep and microseismicity
that occurs before many normal landslides.
Even in retrospect there was not enough monitoring before similar events
at Bandai-san in 1888 and Bezymianny in 1956 to have helped much at Mount St.
Helens.
But now volcanologists know exactly what
to watch for. We now identify
collapse-prone volcanoes from deposits made distinctive by Mount St.
Helens. We no longer expect immediate
precursors to collapse, and we know the roles that over-steepening and
pressurized aquifers can play.
Scientists working on the crisis of Montserrat volcano (including one
with Mount St. Helens experience, Barry Voight) saw in 1996-97 the warning
signs of potential collapse of the south wall of English Crater. Collapse on December 30, 1997, triggered a
phreatomagmatic blast just as at Mount St. Helens. The smaller but still devastating combination of avalanche and
blast swept through homes on the south slopes of the island. Fortunately, all residents had been
evacuated and absolutely forbidden to return.
Sidebar
2: A few sample questions to illustrate uses of
WOVOdat. Each question will be
translated into database queries and grouped into reports. Custom queries will also be possible.
Examples
of questions from volcanologists:
·
Given
developing patterns of seismicity, ground deformation, gas emission and other
parameters, where else has such unrest been observed?
·
--What
happened?
·
--On
this basis, what are the probabilities of various scenarios (including false
alarms)?
·
What
are the most diagnostic precursors to eruptions of a particular volcano, type
of volcano, or type of eruption? This
is a deceptively complicated query as it requires examination of temporal,
spatial and spectral patterns of multiple parameters and examination of unrest
rates and changes in those rates.
·
How
does one particular aspect of unrest (e.g. long-period earthquakes) correlate
with another (e.g. SO2 fluxes)?
·
What
is the significance of a particular change, e.g. sudden seismic
quiescence? From a number of possible
causes which are best supported by the data of WOVOdat?
·
What
does the character of volcanic unrest imply about the coupling and interaction
between magmas, hydrothermal systems and regional tectonics?
·
What
interesting patterns exist in the data of volcano monitoring, especially,
patterns that have escaped prior notice?
(This is data mining.)
Examples
of questions for (and from) students or the general public:
·
What
does volcanic unrest tell us about why volcanoes erupt? What are the necessary and sufficient
conditions for eruption?
·
What
are the most common precursors of volcanic eruptions? Which of these are the most reliable? What combination is the most reliable? How reliable are these one- (day, week, month, etc). before an
eruption?
·
What
systematic differences exist between unrest at volcanoes of one type vs.
another, and how might these relate to magmatic properties and processes?
·
How
often is the volcano in our backyard restless, and how does its current
activity compare with baselines and periods of greater unrest?
Scope of WOVOdat
At
least five general types of unrest will be included in WOVOdat:
1. Unrest
that leads directly to an eruption and is thus a clear precursor to that eruption.
2. Unrest
that does not lead immediately to an eruption but reflects one of a series of
events over an extended time period (e.g., repeated intrusions) that
collectively lead to an eruption.
3. Unrest
that occurs between phases of an extended eruption.
4. Early
phases of an eruption as indicators of what will follow.
5. Unrest
that cannot be related to any eruption, e.g. regional earthquake activity
occurring near a volcano or thermal changes that result only from development
and fracturing of a siliceous self-seal in a hydrothermal system.
A
user who is concerned with why a volcano reawakened this year or decade rather
than the last one might consider all unrest since the previous eruption. A user who is concerned with predicting the
immediate onset of an eruption might consider only the unrest that leads over a
matter of days or weeks to eruptions. A
user who is interested in subtle and not-so-subtle precursors of second or
later phases of an eruption might consider only unrest since the previous
phase.
In
relating unrest to an individual eruption the user will be able to look at as
wide or as narrow a window as data permit.
Certainly complications will arise in generalizations because some
eruptions have multiple phases. Phases
that are closely spaced are often combined as a single phase in Volcanoes of the World (Simkin and
Siebert 1994) unless details about characteristics and dates of each phase were
available. Phases that were separated
by more than 3 months are generally shown as separate eruptions in Volcanoes of the World, even though they
might be from the same batch of magma. WOVOdat will provide time stamps on
everything and the flexibility to look for relations between any set of events.
Information
about the frequency or type or vigor of early phases of an eruption provides
important information about what is to follow.
Much of the information about eruptions themselves is already contained
in a Smithsonian database (Simkin and Siebert, 1994). Additions that WOVOdat will include are quantification of
eruption parameters that are important for forecasting. For example, maximum daily extrusion rate
would be included because fast extrusion rates leave little time for gas escape
and thus gas pressures and explosive potential may increase.
A
preliminary list of parameters to be included has been developed following
suggestions made at the WOVO Planning Workshop and, are detailed on the WOVO
WEB page (http://www.wovo.org/WOVOdat/parameters.htm). A final list, together with suggested units,
data formats and reporting protocols will be drawn up after Phase-III of the
work plan, described below. The
following table summarizes general classes of data into which the large variety
of individual parameters can be fit.
Non-gridded
time series:
Continuous high or low rate Continuous
seismic trace; tilt data every 10 minutes
Triggered high or medium
rate Triggered seismic
traces (event waveforms); tilt data every
15 sec if a certain rate is exceeded in the
10-minute data.
Occasional
data that apply to SO2
flux; magma discharge rate e.g., rate of dome
the
volcano as a whole. growth
Calculated, cumulative data Cumulative seismic energy release,
running b-values
Gridded:
Uniform
sampling DEM’s, geologic maps, seismic
tomography, InSAR interferograms, GOES thermal image data
Time-space
point data Earthquake
hypocenters, fault-plane solutions, x-y-z coordinates of GPS benchmarks, elevations
of precise leveling benchmarks, fumarole T’s, spring discharges,
Images:
Photos,
remote sensing images Photos
of volcano and its eruptions; images rectifiable to a DEM, snapshots of
seismograms that aren’t otherwise digitized.
Video Time-stamped
video clips of explosions and other events that can be correlated with and
explain monitored unrest.
Text:
Primary
index fields Volcano
name and catalogue number; eruption years, types and magnitudes; bibliographic
data, author, title, etc; name, telephone, address, email of contacts, etc.
Free-form text Notes,
longer narrative descriptions.
Definitions: Definitions
of earthquake types VT, LP, etc.
Station information Location, dates of operation, site
characteristics
Network
information Seismic
velocity model, hypocenter determination technique, geodetic reduction
technique, gas analysis technique
Instrument
information Model,
gain, calibrations; response; for satellite remote sensing data, spectral and
on-the-ground spatial resolution.
System Design
The
WOVOdat system can be thought of as having three parts, input modules, output
modules and the database itself. The
design of the fundamental schema for information to be contained in WOVOdat will
be at the heart of this project. A
computer specialists in modern database engineering will be hired to do the
technical design and will interface with the computer specialists at IRIS and
UNAVCO on technical details of data exchange.
The schema will be developed to retain as much high-level generality as
possible to allow the easy addition or modification of lower level elements as
the system develops and matures. Once a
basic framework is defined, simple example input and output models will be written. These can then be modified and adapted to
other types of data or for the same type of data from different sources. The fundamental database engine will be
MySQL for this development work. This
DBMS is open software, relatively powerful and runs on many different
computer platforms. It has many of the
advanced features needed for this project such as fixed and variable-length
records, large number of data types, FULLTEXT
search, multi-level security, high scale-ability, easy IP connectivity and
a large suite programming interfaces (APIs).
The
overall WOVOdat project has five phases:
I.
Concept development and approval from member
observatories (completed)
II.
Database design and development of preliminary
data entry tools
III.
Pilot testing and revisions to design as needed
IV.
Populating the database
V.
Maintenance and Enhancement (stable use)
Phase I, Concept development and approval
from member observatories:
(completed)
At
the first WOVOdat Planning Workshop in Denpasar, Indonesia (July 23-24, 2000),
forty participants from 18 countries, 17 WOVO observatories and the Smithsonian
Institution’s Global Volcanism Program discussed general and specific issues
pertaining to WOVOdat. Based on this
workshop (ed- and a second workshop,held Dec 11-13, 2000) (http://www.wovo.org/WOVOdat/plansum.htm)
a detailed list of parameters relevant to volcanic unrest was drawn up (http://www.wovo.org/WOVOdat/parameters.htm).
In addition, a list of
potential user groups and approximately 50 common searches of WOVOdat has been
developed based on the workshop and subsequent communications and is available
on the WOVO Web pages.
Part
IIA -- Requirements analysis: Interviews with volcanologists will check
and supplement our preliminary understanding of how they use, enter and store
their data; what their current needs are; what questions they currently ask of
their data; what they anticipate their future needs to be (future technologies
and techniques); what types of information gained from WOVOdat would be
beneficial to them; how quickly they need their queries returned; and what
their current database skills are.
Throughout this process we will collect sample data sets. We will then continue the interview process
with a group of educators and students to determine their needs, ideal data
formats and database skill levels. In addition, a small group of scientists
from other fields will be interviewed.
Part
IIB -- Data Analysis/Logical Model/Schema Design: We will review the preliminary data types
and scientific business questions in
part IIA to expand our initial logical model. At this stage we will prioritize
the list of anticipated questions and expand the set of basic reports (views
and view summaries) that will define the database and presentation interface.
We will ensure that the basic reports answer the highest priority questions and
that the multiple lower priority questions can be answered by custom
(handwritten) queries. As with any design process, we aim to design a flexible
model such that future questions can be incorporated into standard reports.
One of the primary challenges of designing a
database of this complexity is to determine how to identify and analyze
patterns and then how to display the returned information. We will begin by
translating our set of common questions (examples in sidebar 2) into formal
queries to determine what data is needed and how it must be organized. To
answer a simple question such as where have specified gas emissions been
observed and what was the outcome, we could write a query to select all
episodes of unrest in which emission of gas g
is greater than mass m during period t and link to the Smithsonian’s file of
historical eruptions to learn the outcome.
From these basic queries, we will organize the database for
multi-component questions that examine changes in seismicity, ground
deformation (x, y and z coordinates), gas emissions, etc. for a period of
time. Rates and acceleration or
deceleration of rates will always be queried, as they are often more
informative than simple magnitudes. We
anticipate that the translation of scientific questions into queries and
reports will take considerable time.
In creating the schema we will be working on
balancing varied user requirements, database maintenance and query
performance. Preliminary conversations
have indicated that interactive query returns on the order of a few minutes are
most useful and common. Our schema will
therefore be developed to handle these types of queries most efficiently.
Preliminary conversations about the data types at each of the volcanic centers
have shown the data collection to be uneven in space, time and quality. We will explore using XML as a data
definition agent to allow for this type of variability and for future adaptability. One of the goals of this project is to help
set voluntary standards for future data collection.
Part
IIC -- Sample Data Population - We anticipate work
with several volunteer WOVO observatories and a small sample of recent data to
create basic scripts for data extraction, loading, mapping, cleansing and
validating.
Part
IID – Presentation Interface Development – Initially all
queries will be hand-written and grouped into reports for test purposes. Once we are satisfied with the standard set
of reports we will work to simplify query development and refine the
presentation interface. Access to the database will be provided through a
standard web interface.
We will also make sure that basic documentation
is available for use by the QA team in Phase III. Additional training materials
will be developed as parts of Phase IV and Phase V with the goal of making the
database easily accessible to all user groups.
Phase III: Sample testing
Preliminary sample testing
will have occurred as part of the presentation interface development process. Once we are satisfied with the results for
our standard reports we will begin a larger QA cycle using the pilot cases of
volunteer observatories.
Specifically
we will test to be sure that the schema and data management utilities are
optimized for data entry, archiving and both standard and custom queries. Utilities will be improved as needed, as
will scripts for standard queries. The
overall test of the design and utilities will be that a user can quickly gain a
clear overview of pertinent data, including the character of an episode of
unrest and easily execute all standard and most custom queries.
Phase
IV: Populating the database:
At
the end of Phase II and III we plan to have WOVOdat in a state to be able to
ingest large amounts of data from many different sources. Through presentations at regular meetings
and through communications to WOVO members the system will be demonstrated and
be available for general use. We
anticipate a large and lengthy task of data recovery, compilation, reformatting
and database loading. It may be as much
as 5 years before the database is large enough to be significantly useful and
longer before most pre-digital data are included and the project is relatively
stable and ready for Phase V.
Most
effort in Phase IV will be by scientists at WOVO observatories. The WOVOdat team will provide modest help as
needed, e.g., with scripts to translate a unique observatory data format into
the WOVOdat standard. The WOVOdat team
will also check contributions as they are readied, to catch any problems early
in each observatory’s effort.
Phase V: Maintenance and Enhancement,
- three parallel tasks.
·
Ensure that data flow smoothly from volcano
observatories and other contributors into the database, with all of the necessary
metadata. We anticipate that WOVOdat
will be so useful that observatories and others will gladly continue their
contributions, but we also know from IRIS and other experience that designated
data managers will be needed to remind contributors to maintain the metadata as
well.
·
Serve data as requested. Most of the data serving will be automatic,
controlled interactively by the users.
Some commonly used data products might be prepared regularly by the
WOVOdat staff.
·
Develop and provide additional tools to assist
users. We anticipate that these will
include teachers' modules for K-12, state-of-the-art data modeling and
interpretation modules, and updates of the data entry toolkit to reflect
changes in monitoring and communications technology. Development of these tools could be started during Phase III or
IV. Basic data query and teacher tools
would be developed jointly by the WOVOdat team and teachers; most modeling and
interpretation tools would be developed and contributed by user scientists.
End
of summary, 05/2002