<p><a href="https://volcanoes.usgs.gov/vhp/lava_flows.html" rel="nofollow noreferrer">Andesitic lava</a> is viscous, compared to basaltic lava. Andesitic lava flows at a rate of a few kilometers per hour, whereas basaltic lava can flow up to 10 km/h. Because of their viscosity, andesitic lavas "rarely extend beyound 8 km from their vents".</p>

<p><a href="https://link.springer.com/article/10.5047/eps.2013.05.018" rel="nofollow noreferrer">Viscosity of andesite lava and its implications for possible drain-back processes in the 2011 eruption of the Shinmoedake volcano, Japan</a></p>

<p><a href="https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2012GC004336" rel="nofollow noreferrer">Pulsatory andesite lava flow at Bagana Volcano</a></p>

<p><a href="https://www.tulane.edu/~sanelson/Natural_Disasters/volcan&amp;magma.htm" rel="nofollow noreferrer">Volcanoes, Magma, and Volcanic Eruptions - Tulane University</a></p>

CC BY-SA 4.0
2019-04-13T21:01:08.640Z
Would you please give your references? tThen i will able to read more from there.
Muharrem Yavuz
CC BY-SA 4.0
2019-04-14T03:07:23.250Z
@MuharremYavuz:  Click on the blue underlined link in the answer
Fred
CC BY-SA 4.0
2019-04-13T09:35:44.490Z
2019-04-14T03:24:08.560Z
2019-04-14T03:24:08.560Z
Fred
<p>During my PhD, I listed many dacite and rhyolite flows, but also included a few andesite flows for comparison. Here are a few interesting examples, first of andesite flows that have been observed while active (for which we have velocity measurements), then of past, frozen flows (for which we have the length only).</p>
<h3>Active flows</h3>
<ul>
<li><strong>Lonquimay volcano, 1988–1990</strong></li>
</ul>
<p>0.23 km<sup>3</sup> of lava, emplaced over 13 months, reaching a distance of 10.2 km from the vent, according to <a href="https://doi.org/10.1017/S0016756800008426" rel="noreferrer">Naranjo et al. (1992)</a>. The article contains nice data of lava flow advance (Table 3), allowing for calculating velocities. The velocity ranged from ~<span class="math-container">$10^{-2}$</span> m/s at the beginning of the eruption to ~<span class="math-container">$10^{-4}$</span> m/s at the end, and the slope from 1 to 6°. You can already see that velocity does not depend on slope, I will come back to this later on.</p>
<ul>
<li><strong>Kizimen volcano, 2011–2012</strong></li>
</ul>
<p>0.30 km<sup>3</sup> of lava, emplaced over ~17 months, reaching a distance of 3.5 km from the vent, according to <a href="https://doi.org/10.1007/s00445-018-1199-z" rel="noreferrer">Auer et al. (2018)</a>. Their Table 1 shows that the slope was much steeper than at Lonquimay (10<span class="math-container">$-$</span>26°), but the flow is not even half as long, with a similar magma volume. Velocity was in the order of ~<span class="math-container">$10^{-4}$</span> m/s (Table 1). Note that this flow is borderline andesitic, involving magma mingling between two components:</p>
<blockquote>
<p>Dark and light bands show a range of whole rock compositions between 62 wt% SiO<sub>2</sub> for the dark silica-rich andesitic endmember and 65 wt% SiO<sub>2</sub> for the light dacitic endmember</p>
</blockquote>
<ul>
<li><strong>Sinabung volcano, 2014–2015</strong></li>
</ul>
<p>0.10 km<sup>3</sup> of lava, emplaced over a year, reaching a distance of ~3 km from the vent. There is a <a href="https://www.sciencedirect.com/journal/journal-of-volcanology-and-geothermal-research/vol/382/suppl/C" rel="noreferrer">whole issue of JVGR</a> on this eruption. This flow reached the same length as the Kizimen one, despite being less voluminous (hence it was &quot;thinner&quot;, with a max thickness of ~100 m, versus &gt; 200 m at Kizimen). The slope was variable: 33° for the first 1 km, 15° for 1–2 km, and 9° for the last 0.5 km. The velocity was ~<span class="math-container">$10^{-3}$</span> m/s at the beginning of the eruption, and ~<span class="math-container">$10^{-5}$</span> m/s at the end, but again <em>this is not due to the change in slope</em> (see below).</p>
<h3>Frozen flows</h3>
<ul>
<li><p><a href="https://doi.org/10.1130/2018.2538(05)" rel="noreferrer">Gusey et al. (2018)</a> describe two andesite lava flows that are among the longest known, with lengths of 52 and 74 km. This gives you an idea of the upper bound. Of course you need more volume to reach such lengths: minimal volume estimates are 2.5 and 6.6 km<sup>3</sup>, respectively.</p>
</li>
<li><p><a href="https://doi.org/10.1007/s00445-016-1020-9" rel="noreferrer">Chevrel et al. (2016)</a> describe several voluminous andesite flows at El Metate volcano. The largest, named F6, is 15 km long, with a volume of 2.2 km<sup>3</sup>. This paper is also a nice example of how you can infer dynamics parameters of frozen flows. For F6, they inferred a velocity in the order of ~<span class="math-container">$10^{-4}$</span> m/s.</p>
</li>
<li><p>Yet another example is the 6.5 km long Oturere andesite flow, at Tongariro volcano, where <a href="https://doi.org/10.1080/00288306.2002.9514980" rel="noreferrer">Stevens (2002)</a> calculated a volume of 0.37 km<sup>3</sup>.</p>
</li>
</ul>
<h3>Factors controlling lava flow length</h3>
<p>As you can see from these examples, andesite effusive eruptions with similar magma volumes can yield lava flows of different lengths. But the main factor controlling lava flow length is not the slope<span class="math-container">$-$</span>it would be if lava was a Newtonian fluid, which it isn't. <a href="https://www.jstor.org/stable/74335" rel="noreferrer">Walker (1973)</a> <em>Lengths of lava flows</em> summarizes it well:</p>
<blockquote>
<p>The principal factor influencing the length of a lava flow is the rate
of effusion. With a high rate the lava flows rapidly from the source
and tends to form an extensive and far-reaching flow which is simple
in character (i.e. made of a single flow unit). With a low rate the
lava tends to pile up layer upon layer to form a local accumulation of
limited lateral extent near the source, and this accumulation strongly
compound in character (i.e. divisible into flow units).</p>
</blockquote>
<p>You can see the correlation between effusion rate and flow length on his Figure 4. Now, the reality is a bit more complex, and much work have been done since, but his assertion still stands true. At Lonquimay and Sinabung for instance, you'll see in the references that changes in effusion rate has been linked to changes in lava flow velocity (and, ultimately, to final length).</p>

CC BY-SA 4.0
2022-11-22T10:30:18.853Z
2022-11-22T10:30:18.853Z
Jean-Marie Prival
<p>For an effusive volcanic activity, how far an andesitic lava can flow?
What is the velocity?</p>
<p>Eruption volume 0.2 km<sup>3</sup> with 25 degree slope.</p>

CC BY-SA 4.0
2019-04-12T05:20:18.063Z
you need to give more information like the volume per hr and the angle of slope.
trond hansen
CC BY-SA 4.0
2019-04-12T20:26:23.917Z
I don't know the volume per hr. Eruption amout 0.2 cubic km amount with 25 degree.
Muharrem Yavuz
<volcanology><fluid-dynamics><volcanic-eruption>
How far can an andesitic lava flow, and what is the velocity?
Muharrem Yavuz
# How far can an andesitic lava flow, and what is the velocity?

(Asked by: username_0 on 2019-04-11)

For an effusive volcanic activity, how far an andesitic lava can flow?
What is the velocity?

Eruption volume 0.2 km3 with 25 degree slope.

**Tags:** volcanology, fluid-dynamics, volcanic-eruption

> **Comments:**
> **username_1**: you need to give more information like the volume per hr and the angle of slope.  
> **username_0**: I don't know the volume per hr. Eruption amout 0.2 cubic km amount with 25 degree.  

---

## 2 answers

### Answer by username_3 on 2022-11-22. Score: 5 | Accepted answer

During my PhD, I listed many dacite and rhyolite flows, but also included a few andesite flows for comparison. Here are a few interesting examples, first of andesite flows that have been observed while active (for which we have velocity measurements), then of past, frozen flows (for which we have the length only).

### Active flows

* **Lonquimay volcano, 1988–1990**

0.23 km3 of lava, emplaced over 13 months, reaching a distance of 10.2 km from the vent, according to [Naranjo et al. (1992)](https://doi.org/10.1017/S0016756800008426). The article contains nice data of lava flow advance (Table 3), allowing for calculating velocities. The velocity ranged from ~$10^{-2}$ m/s at the beginning of the eruption to ~$10^{-4}$ m/s at the end, and the slope from 1 to 6°. You can already see that velocity does not depend on slope, I will come back to this later on.

* **Kizimen volcano, 2011–2012**

0.30 km3 of lava, emplaced over ~17 months, reaching a distance of 3.5 km from the vent, according to [Auer et al. (2018)](https://doi.org/10.1007/s00445-018-1199-z). Their Table 1 shows that the slope was much steeper than at Lonquimay (10$-$26°), but the flow is not even half as long, with a similar magma volume. Velocity was in the order of ~$10^{-4}$ m/s (Table 1). Note that this flow is borderline andesitic, involving magma mingling between two components:

> Dark and light bands show a range of whole rock compositions between 62 wt% SiO2 for the dark silica-rich andesitic endmember and 65 wt% SiO2 for the light dacitic endmember

* **Sinabung volcano, 2014–2015**

0.10 km3 of lava, emplaced over a year, reaching a distance of ~3 km from the vent. There is a [whole issue of JVGR](https://www.sciencedirect.com/journal/journal-of-volcanology-and-geothermal-research/vol/382/suppl/C) on this eruption. This flow reached the same length as the Kizimen one, despite being less voluminous (hence it was "thinner", with a max thickness of ~100 m, versus > 200 m at Kizimen). The slope was variable: 33° for the first 1 km, 15° for 1–2 km, and 9° for the last 0.5 km. The velocity was ~$10^{-3}$ m/s at the beginning of the eruption, and ~$10^{-5}$ m/s at the end, but again *this is not due to the change in slope* (see below).

### Frozen flows

* [Gusey et al. (2018)](https://doi.org/10.1130/2018.2538(05)) describe two andesite lava flows that are among the longest known, with lengths of 52 and 74 km. This gives you an idea of the upper bound. Of course you need more volume to reach such lengths: minimal volume estimates are 2.5 and 6.6 km3, respectively.
* [Chevrel et al. (2016)](https://doi.org/10.1007/s00445-016-1020-9) describe several voluminous andesite flows at El Metate volcano. The largest, named F6, is 15 km long, with a volume of 2.2 km3. This paper is also a nice example of how you can infer dynamics parameters of frozen flows. For F6, they inferred a velocity in the order of ~$10^{-4}$ m/s.
* Yet another example is the 6.5 km long Oturere andesite flow, at Tongariro volcano, where [Stevens (2002)](https://doi.org/10.1080/00288306.2002.9514980) calculated a volume of 0.37 km3.

### Factors controlling lava flow length

As you can see from these examples, andesite effusive eruptions with similar magma volumes can yield lava flows of different lengths. But the main factor controlling lava flow length is not the slope$-$it would be if lava was a Newtonian fluid, which it isn't. [Walker (1973)](https://www.jstor.org/stable/74335) *Lengths of lava flows* summarizes it well:

> The principal factor influencing the length of a lava flow is the rate
> of effusion. With a high rate the lava flows rapidly from the source
> and tends to form an extensive and far-reaching flow which is simple
> in character (i.e. made of a single flow unit). With a low rate the
> lava tends to pile up layer upon layer to form a local accumulation of
> limited lateral extent near the source, and this accumulation strongly
> compound in character (i.e. divisible into flow units).

You can see the correlation between effusion rate and flow length on his Figure 4. Now, the reality is a bit more complex, and much work have been done since, but his assertion still stands true. At Lonquimay and Sinabung for instance, you'll see in the references that changes in effusion rate has been linked to changes in lava flow velocity (and, ultimately, to final length).


---

### Answer by username_2 on 2019-04-13. Score: 5

[Andesitic lava](https://volcanoes.usgs.gov/vhp/lava_flows.html) is viscous, compared to basaltic lava. Andesitic lava flows at a rate of a few kilometers per hour, whereas basaltic lava can flow up to 10 km/h. Because of their viscosity, andesitic lavas "rarely extend beyound 8 km from their vents".

[Viscosity of andesite lava and its implications for possible drain-back processes in the 2011 eruption of the Shinmoedake volcano, Japan](https://link.springer.com/article/10.5047/eps.2013.05.018)

[Pulsatory andesite lava flow at Bagana Volcano](https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2012GC004336)

[Volcanoes, Magma, and Volcanic Eruptions - Tulane University](https://www.tulane.edu/~sanelson/Natural_Disasters/volcan&magma.htm)

> **Comments:**
> **username_0**: Would you please give your references? tThen i will able to read more from there.  
> **username_2**: @username_0:  Click on the blue underlined link in the answer  

---

